When I boot up my PC there is no signal to the monitor and I do not hear any POST beeps. If I wait a while (it varies a lot; 30 sec to 3 mins +) it eventually starts up and works fine - never crashed. This is a new PC and the prob started to happen 1 week after I purchased it. It is getting worse and worse. I will take it back if I can't get the prob fixed myself. I checked that all cables are seated properly and heat does not seem to be a problem according to the BIOS reading and ASUS PC Probe. The specs are:

Intel Pentium 4 2.60C GHz, 800 MHz FSB, 512 KB Cache, Hyper-Threading
ASUS P4C800 Deluxe, Intel 875P Chipset
Antec Performance Plus 1080AMG with Windowed Slide Panel
Antec TruePower 430 Watt
Corsair 1024 MB TWINX XMS3200 400 MHz CL2
Sapphire Radeon 9800 Atlantis Pro 128 MB DDR
Creative Sound Blaster Audigy 2
Creative Inspire 6.1 6600
Seagate SATA 80 GB, 7200 RPM, 8 MB Cache
Lite-On 40X/16X CD/DVD
Lite-On 32X12X40 CDRW
Sony 3.5" Floppy Disk Drive
Logitech Elite Keyboard
Logitech MX500 Optical Mouse

Sounds like it might be heat related within the monitor itself. If it is possible for you to connect another monitor it would easily rule this out. does this happen when the system is hot and first started, like running it a while, then shut down, and start it back up? If not, I'd still say it is heat related. Thermal problems are not always related to things getting too hot, sometimes a faulty component will work fine after it gets hot, and only show problems when it is cold, and vice versa.

If it were just the monitor, I should still be able to hear the beeps from the system as it goes through the power on self-test. Since I don't hear any beeps I would say it's a hardware problem within the case.

The problem happens all the time, whether I has been booted after running for ages, or booted after a day of not running.

My friend has had a problem similar to this. Being carefull, you can remove a stick of RAM out and see if it boots. If not, switch it with the other stick. If you get it working, go ahead and shut down and stick the other stick back in, boot up, and it solves the problem mysteriously in most cases. If when sticking in the second stick of RAM, and it doesn't boot, take the second stick out again. If it boots, double check, then you can come to the conclusion that you've got a bad stick of RAM.

You shouldn't have to do all this work yourself. Take it back to the peeps that sold it to you. Tell them to fix it. If they can't, say you want a refund.

Thanks for all your advice. I don't think I should spend my time figuring out the problem. I'll take it back soon, once all my exams are over and I have time.

Just advice: make sure they will take it back and can take it back and see how long you have till you can take it back.

It's your PSU that is broken. To check that out for sure, try a hard reset (reset button). I bet your PC will start promptly after the reset. Your PSU doesn't provide the right voltages to get your PC booting. With that reset you boost the initial voltages and reach the correct values. Or you can wait 30s-3 mins until it 'charges up' by itself.

Sorry ToRN, I don't quite understand what you mean by "try a hard reset".

I think she means once its up and going, press the reset button. It should fire right up off a reset, instead of you having to wait 30-3 minz off a cold boot. It sounds like the PSU is having to 'charge up' for your PC to boot.

The reason your PC should start right up again after a reset, is becasue the PSU has already charged itsself from when you did the orgional cold boot.

So get your PC up and running, then press the reset button. When it resets do you still have to wait all that time?

I think HE means. Okay, I'll change that avatar, but I am not a girl... (I do understand the confusion though)

awe gosh, im sorry

Yeah, if my PC is aready booted, and a hit the reset button, it starts fine. So this means my PSU is broken and needs fixing. Correct?

Not necessarily, it means the problem is somewhere in that general area though. It could be in a connection between the motherboard, PSU, and case buttons. Or the problem could be in the PSU. Check the connections first, then look to the PSU. The problem may not be that it is broken. It may be that it is not supplying enough current on the 12v rail.

But if its not supplying enough current on the 12v rail, its good enough to chuck right?

No it isn't. Different PSUs supply different amps on the rails. Some are rated higher than others. Todays higher end hardware needs more current, especially on the 12v rail. If your PSU is rateed at less than 17A(minimum, I'd recommend more) on the +12v rail, it probably isn't oing to be enough to properly supply power for recent hardware.

The current(A) rating is more important than the wattage because you could have a 500W PSU, but if it isn't capable of supplying proper current to the rails, it still won't be able to power the system properly.

From the reviews that I've read, the Antec TruePower 430 Watt PSU seems pretty good, but I don't understand half the tech jargon when it comes to power supplies. Specs for this PSU can be found here http://www.antec-inc.com/specs/true430_spe.html but I don't know what half of it means.

Look down at the Output values, you'll notice it says +12V has a max of 20A, this should be enough, so you may have a fault in the PSU. that is if you have checked the connections as I recommended earlier and tried all the other recommendations made by others and none of it works.