Ok...I'm pretty new to the ins and outs of PSUs so I will try and give as many details as I possibly can about my PC and what I have tried so far to sort out my problem...please bare with me.
Firstly, my PC runs fine, it is only when I play a game that the black screen loop sound problem happens...it is not even a power sucking game like warcraft or CoD2, it's Medal of Honor spearhead which is about 4 years old now...anyway, my specs..
INTEL PENTIUM 4 560 3.6GHZ 800mhz FSB/HTT/1MB
2048 MB DDR400 PC3200 (2x1GB)
ASUS P5P800: DUAL DDR, S-ATA, 8X AGP, 5 PCI, ATA133 ETC
SATA 250 GB HARD DISK @ 7200rpm 16mb cache
256MB GEFORCE 6600 8X AGP + DVI + TV-OUT
SoundBlaster Audigy 4 7.1 Pro + External Kit (breakout box)
550w PSU (warranty replacement for a 500w that died) generic

now a little history...
I bought this PC about a year ago and it came in quite a small case that I was not happy with as it was locking up on startup because the case was overheating, took the side off and it started up fine...I had the choice of sending the whole thing back (and waiting another 3 months because the company that built the thing couldn't work out why it was crashing in the first place) and get a new case or buy one myself and do it...so I bought this (my link) Thermaltake case and installed everything.
It worked fine for about 3 weeks until I started getting random crashes when playing Medal of Honor.
After many many hours of research I have unistalled/reinstalled the game, did a format, used driver clean pro, reset my cmos, updated my bios, ran memtest for 11 hours, optimised my airflow by taping back all possible cables that would disturb it...I've cried, shouted and bored my girlfriend to almost suicide with my rantings about what I've done.
Now I'm running this thermaltake PC with 7 fans all in all (including the graphics card fan) with the side off and it still crashes...I have to open a window to even get it to run at 800x600 medium settings in the game...I found my cat on the window ledge of our appartment last night, and being a few floors up I pondered whether he was just looking or was ready to jump because of my obsession with this!!
I have done a front and rear fan speed check in bios and my fans are running a bit below par? The front fan is running at 1328rpm and the rear is 1288rpm...both fans are supposed to be 1400rpm.
I have also noticed a hotspot on my graphics card right in the corner next to the motherboard when I play the game...I have a (my link) Gigabyte G-Power Cooler Pro CPU fan which sticks out about halfway across my rear fan...could that be disrupting airflow and therefore causing the hotspot? (I do have a pic of the inside of my case but my digital camera is not being reconised by USB at the moment ) I'll post a pic tommorow if anyone needs to look at it?
I'm basically at my wits end with this problem (so is my girlfriend and cat)....I'm really leaning towards the PSU, I did think that 550w was ample for a machine of my size but considering that I am running a lot fans and externals off the power supply it may not be and I'd like someones second opinion...like I said I've never really dabbled or thought about PSUs as the problem...I even returned my graphics card under warranty because I thought it was flakey...could someone give me their opinions and save a poor woman and a cat from an obsessed temperature maniac??
thanks.

P.S
Looking at the link to my Thermaltake case it says that front and rear fans are 1300rpm but on the box it came in it says that they are 1400rpm?

If you have THAT many fans it doesnt sound like a overheating problem. Have you tried a using a program such as speedfan to see how hot your parts are?

What make/model is the PSU. What are the amps on the 5 and 12 Volt rails? You can read this off the label on the side of the PSU. See my sig line below for an example.

I check your spec at psuCal and it showed 300W. But you'll need about 22Amps on the 12V to run safely.

Also make sure your chipset drivers for the mobo are up to date and what version of nvidia driver are you using? There's been a new release lately you might try that. Dwnload from nvidia website.

One last thing, do a search here for Audigy souundcard. I remember reading a post about this crashing some games. You might try uninstalling it for now to see if that helps.

Cheers.

all the case fans in the world won't do much with the side panel of your case off. if you leave the side panel off and it's getting too hot, then position a small house fan to blow air towards the sid of your case (do not put it right up to the side, about 1 foot away would be good)

If you have 7 fans then you should configure 3 of them as intake fans, with the remaining 4 as exhust fans. the fans on the front and side should be intakes, the fans on the top and back should be exhaust, this will create a more blanced flow of cool air inside your case and minimize the fans all fighting each other for air. of course you need to put your side panel back on for this to be effective.

a generic PSU will not even come close to providing 550w, it probably puts out about 250w-350w, and most of that power will be on the 3 and 5 volt rails, but not on the 12v rail where it is needed the most.

because of this, you cannot go by wattage to determine if a PSU is powerful enough. wattage = voltage x amperage. the total wattage rating of a PSU is the sum of all rails. cheap/generic power supplies will have high amperage on the 3v and 5v rails, and low amperage on the 12v rail <--a power supply with those specs will have a high wattage rating, but will actually be a weak and insufficient power supply.

and to top it off, a cheap/generic power supply will not have good voltage regualtion, which can lead to system crashes or even permanent damage. also, there will be very little (or none) protection circuitry to prevent the power supply from frying the rest of your components if it goes.

bottom line is that whether or not it is the source of your problem it would be very wise to replace it with a quality power supply. I recommend Antec, but there are other good qualtiy brands as well. here's a good guide for selecting a good PSU with enough power for your system.

good luck

Thankyou for all your replies so far...
Kirock, I've been down the chipset/update Nvidia/Audigy drivers path but to no avail.
Kingcody, with the side of the case on the problem is worse
all my fans are flowing in the right direction I.E front sucking in, back and top blowing out.

Ok....I managed to get out my PSU and get all the details off it, the PSU is an EZcool 'super silent' switching mode PSU ATX 550w JSP (socket 775)
After doing a search for it I am a little peaved to say the least!! this was a replacement under warranty for a 500w fan that cost me £35...the EZcool comes in at a cheap £19!!
Here are the other details I gleamed off it
Pentium 4
1.High Efficiency
2.Low noise & ripple
3.Short circuit protection
4.100% burn in/vibration test/HI POT test/leakage current test
AC INPUT 230-5A. 50HZ
DC +3.3VDC/max output 30A
DC +5VDC/max output 32A
DC -5V/max output 0.5A
DC +12VDC/max output 36A
DC -12VDC/max output 0.8A
DC +5VSD/max output 3.0A
PS-ON=REMOTE
COM=RETURN
POK=PG

Now this doesn't mean much to me but I hope it helps?

I went into bios hardware monitor and here are some stats...

CPU Temperature 47.5c/117.5f
MB temp 28c/82f
Q-fan disabled
CPU fan speed 2033rpm
VCORE voltage 1.392v-1.400v (fluctuating)
3.3v voltage 3.408v
5v voltage 5.324v-5.401 (fluctuating)
12v voltage 12.196v-12.302v (fluctuating)

These are just in normal running but I know when I play the game the temp around the graphics card (especially in the corner at the rear of the card gets quite hot) it can last 5 mins, it can last an hour until the PC just gives out the black screen of death and the sound crackles and loops?
Hope some of these stats have helped and thankyou all for applying your braincells to my problem.

Well if that means what I think it means you're right, the psu is to blame. But could you tell us what temperature the graphics card is running at anyway? And an insulting question I know, but just in case, did you connect the molex(multi coloured cable) cable from the graphics card to the psu? It does sound like a psu problem though, bloody generics...

Thanks paranoid...
I dont know how to monitor the temp of my card...especially 'in game'
I did find this guide for my card but I'm not very confident about pulling it off and wouldn't like to try it TBH?
http://www.ocia.net/articles/tempmonitoring/page1.shtml

As for the molex connectors, this card is a replacement for the original that I sent back because I believed the crashing was caused by the original being flakey. The original had a molex connector on it...this replacement doesn't...it runs out of the AGP slot on my motherboard.

Really? That's a bit unheard of in my (limited) knowledge, 'specially for a 6600.
Download speedfan: http://www.almico.com/sfdownload.php
and it should tell you what your card's temps are. Sounds like the card isn't getting enough power, which is now not at all suprising, what with the dodgy psu and the lack of a molex cable. We'll soon know though. (I hope)

Edit: Do you not have a control panel for your card in your quick items? Called nvidia display? My speedfan doesn't actually tell me specifically the card's temperatures, I just checked, so scratch that. Anyway if you have that nvidia settings down in the corner that'd be handy, just click it and click temperatures.

I downloaded speedfan but it seems to be only monitoring my CPU fan and 1 of my sys fans (my motherboard only has the capacity to monitor 1 fan) flakey yes...if I need to check front and rear I have to swop the plug into the motherboard.
In readings on loading up I got this read out

Win9x:NO 64Bit:NO GiveIO:YES SpeedFan:YES
I/O properly initialized
Linked ISA BUS at $0290
Linked Intel 82801EB ICH5 SMBUS at $0400
Found nVidia GeForce 6600 GT
Linked nVidiaI2C0 SMBUS at $3D403E3F
Linked nVidiaI2C1 SMBUS at $3D403637
Linked nVidiaI2C2 SMBUS at $3D405051
Scanning ISA BUS at $0290...
Winbond W83627EHF (ID=$88) found on ISA at $290
SuperIO Chip=Winbond W83627EHF
Scanning Intel SMBus at $0400...
Scanning I2CNVidia SMBus at $3D403E3F...
Scanning I2CNVidia SMBus at $3D403637...
Scanning I2CNVidia SMBus at $3D405051...
SMART Enabled for drive 0
Found Maxtor 6L250S0 (251.0GB)
Bad Thresholds Checksum ($17)
End of detection
Error loading event -->
CfgVersion=01.0001
EventsVersion=01.0001
Loaded 0 events

I have
sysfan at 1298rpm
cpu0fan at 1974rpm
aux0fan at 0rpm
cpu aux fan 0rpm
aux1fan 0rpm
I checked the fan on the card and it is running fine?
On the read on the right I'm getting

(arrow down) Temp1:29c
(tick) Temp2:26c
(flame) Temp3:120c
(arrow down) HD0:31c

Like I said I'm fairly new to this but a flame icon is not a good sign??

120 Degrees celcius!!!
That's dangerous.
Do you have another graphics card you can try? It sounds like the 6600 isn't getting enough power, and it's overheating. A lot. You need to get a new psu I think and there has to be a connection for a molex cable on that 6600. You should be able to pick up a cable for a few quid and that should fix this.
And can you see if you have a nvidia settings icon in your quick items(in the corner of the desktop beside the clock)

oh dear
I just had the card out to check again and there are NO connectors anywhere on the card apart from a small pin one that runs the fan on the card??
The original card was a chaintech (with molex), this new one is a inno3D (without)
I dont have any other cards I can cross check with...
I do have the nvidia setting icon on my quicklaunch bar but there are no options for monitoring temperatures...it seems to be disabled as in the link I posted above about enabling, its a bit too complicated for me but I'll give it bash as a last resort...it involves messing with the graphics card's bios settings and I'm savvy enough for that.
I'm getting very worried.

Em... I wouldn't recommend doing that, sorry I was unaware that you just had no temperature monitoring enabled, that sucks but it doesn't matter. If the card didn't come with a cable and it doesn't have a connection for it anyway, it's just a psu issue. So I suppose you're looking at getting a new psu. Sorry to be the bearer of bad news.

"I'm savvy enough for that"
sorry that should have been a resounding NOT savvy enough!
yeah..I dont fancy messing around with the card's bios and using hex editors.
I've been doing some reading and it seems very strange that my 6600GT doesn't have any molex connectors? I haven't seen it mentioned anywhere...the original card was a chaintech and this replacement is an inno3D, running a 256MB card just out of the AGP slot sounds a bit weird?
I read a few reviews for my replacement PSU (the EZcool one) and it doesn't look good...cheapskate company replaced my 500w £35 PSU with a £19 bum one?
Thankyou very much for your time on this problem...you and others have helped me a lot.

the no molex problem is solved...
seems that some versions of the 6600 have no molex? When I received my build it had a GT card in it with GT drivers...the replacement is a 6600 (only cheap 6600's come with no molex) but this card also came with GT drivers??....My display properties say Ge-Force 6600GT at the top....so it seems I'm running a 6600 on 6600GT drivers...I assumed that the new card was just a different design of the 6600GT by a different company.
this is probably contributing to the overheating problem.

Just return the 6600 card, if you paid for a 6600GT, there's noway in hell they should try and pawn off a 6600 on you instead. The difference in performance bewteen those 2 cards is huge!

Also the card sounds defective, noway it should be 120C, there's something wrong with the HSF on the GPU. But this isn't your problem b/c this isn't your card! Your card has yet to arrive.

Cheers.

BTW, your PSU seems to have the amps required to run your specs, but if it is a cheap low end generic, then it's efficiency is probably terrible and running heavy 3D games might still push it to it's thermal limits. Just keep an eye on it after you get your proper 6600GT installed.

Thanks kirock...
This gets weirder, I just rechecked my specs again at the company I got to build my system (card specs can be seen in my first post) It says my order was a 6600 not a GT yet I ordered a GT and it came with a GT?? So what I'm guessing is the builder read the right order (GT) and installed one....some admin person put 6600 on my order on their database, whoever sent out my replacement sent a 6600....I'm going to phone them up in a bit and ask them what the hell is going on?? But why did the 6600 come with GT drivers? I'm going to use driver cleaner pro later and install forceware 91.31 to see if that goes some way to solving the problem (at least I'll have the right drivers)
I'm also worried about the fluctuating voltage readouts in my bios...seems my PSU replacement is not all that good, could this possibly be anything to do with the power coming into the PC from the wall socket? My case is plugged into a seperate socket and my monitor, hi-fi, wireless mouse power etc is plugged into a 4 socket extension....it's probably just the PSU though.
I should have known this company was clueless when it took them 3 months to complete my build because they couldn't work out why my PC constantly crashed on start-up....the case they chose for my build was too small for the components, I sussed that within an hour of getting my order....unluckily they had already taken my money out of my bank, next time I'll do it myself.
thanks again everyone....I'll get there in the end!!

bet you guys are getting sick of me :haha:
Updated my drivers to 91.31...loaded up medal of honor and got a black screen crash after 2 minutes, the card was super toasty and there was that circuit o3 smell in the air :dead:
This really is driving me nuts!!
The company are sending out a GT card in a few days so that will be good but I am also going to buy a new PSU
Thankyou for your guide kingcody...I've had a poke around and I wanted to get the OCZ PowerStream 520w but it seems non existent in the U.K? so I'm going to go for the Thermaltake W0057 500W PurePower Modular...if anyone could point me to a reliable PSU similar to those and around the same price (about £70) it would be much appreciated
thanks everyone.

Just a point about the drivers: It actually doesn't matter if it's GT or not or if it's a 6600Gt or 7900GTX, the drivers from nvidia are common for/via the OS you're running and the CPU type (i.e. AMD vs. Pentium)(this determines the chipset).

A little flucuation in voltage is common, if it the range of flucuation is greater then 10% of the nominal voltage then you have a problem. A good quality PSU pegs this variation at less then 5%. It's a little weird with switching mode PSU (all PC PSU are switxhing mode), under very little load the voltages will vary to their maximum and under heavy load they will flucuate even more. Somewhere in between they work well and the voltage flucuations are minimum.

Antec, OSC, Thermaltake, Enermax are good quality PSU you should look for.

Cheers.

I've been doing a bit of reading about AGP aperture settings in bios apparently the aperture is relative to the amount of ram you have, seen as I have 2gigs of ram I increased the aperture to 128mb (it was set at 64mb). Medal of honor looked a lot better and it ran for 15 mins with the side panel of the PC on and without any windows open in the room and there was no sign of crashing at all
I'm going to run it for longer later tonight to see if it holds up?
Anyway guys...
new card (GT) on the way
Thermaltake purepower 500w PSU ordered and on the way...I also ordered another 120mm fan to go on the front of the case (making 2) for extra air intake.
I'd just like to thank everyone who helped with my problem
This is a great forum.
I'll let you know how it all goes.
thankyou.