Dell Dimension 8100 Will Not Boot After Shutdown

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TS Rookie
I have a Dell Dimension 8100 computer that I inherited from my stepdad. I know for a fact that he bought two new sticks of 512 rambus mem. as an upgrade before he gave the computer to me.

The reason he gave it to me was because he said it was "on the fritz" and he had bought himself a new computer anyway. (AMD Athlon with 64 bit architecture).

After shutting down the computer it will not reboot for about an hour to sometimes about an hour and a half. It sounds like it is booting up but never powers up the monitor.

I have read similar posts to mine and have followed the recommendations in them. I am getting a yellow A-B and green C-D which means it is not booting the memory correctly and i have tried over and over to reseat the memory and it still does the same thing.

Once it does actually boot i can go into the bios setup and see that is recognizes the memory as two sticks of 512 rambus mem. but then when i look at the total memory count it is only 960. Coversely, when i right click on my computer in windows it says I only have 960, but when i go to the system information window it says i have 1024. So what gives?

Is this a motherboard problem, a memory problem, or possibly something else.

My friend has a theory. he says that heat can casue the pins in the memory slots to droop and not contact the memory correctly and therefore that is why it seems the board must go through a cooldown period before booting again.

I am desperate to get my computer working correctly again!!! Imagine not being able to restart when you need to!!! Please help!!! Thanks.


TS Rookie
Oh yeah, I ordered a new Dimension 8100 specific 410 watt power supply from to replace the existing Dell 250 watt stock PSU.

I know the mobo diagnostic code is saying it is a memory problem but i am still skeptical.

I really need some help here!! Here is some more information about my pc:

Dell Dimension 8100
Stock 250 Watt PSU
Pentium 4 1.4 Ghz Processor
1024 Megs Rambus Ram
2 7200 RPM 60 Gig HDs
Nvidia GeForce 3 64 MB GPU
USB 2.0/Fireware (3 and 2 slots respectively) PCI Card
Turtle Beach Santa Cruz Sound Card
56k modem (just collects dust)
DVD ROM Drive (LG)
DVD Burner (Sony)
Zip Drive (is not hooked up to power supply though)
3 1/2 floppy drive
Windows XP Home Edition


Altec Lansing Power Cube Speakers
19 inch monitor
Standard Keeboard
Microsoft Intellimouse Optical
Saitek X52 Flight Control System (Awesome, You need one)
DVC 150b Video Capture Device
Net Gear 54mbps Wireless Router
Compaq Pocket PC
HP Photo Printer with data card reader (SD, etc.)
Visioneer Scanner
Cable Modem
Creative Webcam

And probably more stuff that I am forgetting. As you can see I love my computer and I love computing and especially gaming. I have over 150 PC Games in my collection with new ones like HL 2, COD 2, Far Cry, Battlefront 2 etc.

I am upgrading to the 410 watt power supply and a new ATI Radeo X800XL video card (or possibly a slightly better model).

My computer works fine when it boots. It's getting it to boot after a shutdown or trying to restart it that doesn't work.



TS Rookie
Guys, I really need your help!!! I see that people are reading my post but no one is offering any advice! HELP ME PLEASE!


TS Rookie
Ok computer gurus.. what gives? You have a fellow nerd in trouble with what seems like a fairly common problem and yet no replies and no offers of advice.. I'd appreciate any suggestions.

Again, my computer will boot only after about an hour to and hour and half of being shut down. What the heck is that? After that it works fine most of the time. Sometimes it will crash though during weird things like trying to activate a profile for my Saitek X52 flight control system. When i do that it makes a sickening sound, flashes up a blue screen for too short a time to read anything on it, and then shuts down, not to be rebooted for you guessed another hour or so. Weird huh?

Any comments, suggestions, ideas. Please guys I am desperate. Thanks for anything you can offer!!


TechSpot Chancellor
the purchase of the PC power and cooling PSU was a good move.

you should inspect the rambus modules, it sounds like either one of them is defective or they are not matched. make sure they are BOTH either .45ns or .40ns. it is listed on the label of the modules.

the unit should also have a service tg number on it. got o dell4me and the support section and enter the tag number and check for any bios updates for your machine.


TS Rookie
Thanks for the reply.

I know the modules are matched (i think i do anyway) because they were bought as a pair from the same company. Can't remember what the brand is, i'll have to look again.

I do have that tag number, just haven't called tech support about it yet because it is always some lady or dude in malaysia or taiwan that can barely speak english reading from a script. I am really not satisfied with Dell's support but the computer was a gift so I can't really complain all that much.

As far as the BIOS update goes, i have found one but I am reluctant to do it for two reasons:

One, i recently ruined a D-Link wireless router by trying to update the firmware (no there were no power outages or surges it just hung up in the middle of the update) and killing my mobo scares me.

And two I don't really see how that would affect or fix my problem. How would an out of date bios prevent the monitor from coming up during the the boot up process for the first hour after a restart attempt but not an hour later? So weird. Anyone ever heard of anything like this?

Also, what are the chances that the PSU will fix it? Won't come in til Thursday I think.

And lastly, how do i find out if this is a motherboard or a memory problem?

Thanks for your advice!


TS Rookie
Ok, this is weird. I replaced the power supply and it isn't completely fixed. However, it will boot up after only 20 minutes or so now. But it isn't compeltely fixed and i'm still getting the Two yellow A-B and green C-D (bad memory code or something).

Also, i thought the fan in the old PSU was going bad. Turns out that it is the Case/CPU fan, i can hear the bearings squeeking. Anyone ever heard of a case fan messing with the mobos power up cycle? I'm going to best buy tommorow to get a new one.

Next i am going to either geek squad or somewhere local for a diagnostic. I'm tired of not knowing. What a headache. Also tommorow i get my new video card. This is never ending....

Motherboard = 100 bucks
Memory = 250 (two 512 rdram from samsung)

hope it is the mobo and not the memory.. or both.


TS Rookie
Urgent Help

Hi this is my problem: I have a dimension 8100 and I upgrade the memory, everything works fine,until today when I connect a new mouse and don't recognised so I desconnect the computer from the power supply and when I connected again does not boot, nothing is working only a amber light appear in the motherboard and in the front botton, when i press the botton change green but automaticly comback as amber.

Thanks please Help me.
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