Ok, so i was recently having problems with my evga e-geforce 6600 LE and my ABIT AN8 SLI. First there was no post screen whenever my videocard was in the first PCI express slot, so I returned it and got a Sapphire Radeon x700 Pro. I get a post screen in the first slot with this card, but once i get past the WINDOWS XP loading screen, I get "IRQL_NOT_LESS_OR_EQUAL" everytime. I've been having many problems with this IRQL thing since my computer was put together a month ago. I even went to Fry's electronics to change my motherboard. Got my motherboard changed, still have problems. I've also ran ram tests and seem to have found no errors. I also bought a power supply adapter to fit into my 24 pin motherboard. I can never seem to get my computer working right. Help?
Wow, you're describing my life!
I have the EXACT same problem for about a month now.
In my case it only happens once a day. If I turn on the computer, it blocks afeter the Windows XP logo with the 0x7f, 0x50 or 0x8E blue screen error, depending on the day...
I reboot, enter safe mode, open a few files, open the browser, reboot, and then it works perfectly for the rest of the day, even if I stop it, an start it again.
Only the next morning it does the same thing again, extremely weird.
A8N-SLI Deluxe (1016 BIOS)
1GB Kingston DDR400 (DualChannel)
Conect3D x700Pro w/ Zalman cooler (stock one broke down)
Hitachi 160GB SATAII
2x WD 40GB IDE
Tagan 480W PSU
Memtest isn't perfect, the IRQL error is usually a memory problem. In your case it might be only happening in windows mode because the system uses more power, which it has to draw from whatever your power supply is.
Of course the memory problem might just be that, a memory problem. Try increasing VDIMM to 2.8v