I'm experiencing random system lockup and rebooting without any BSOD or error messages. I've formatted and re-installed Windows XP Home edition, and have performed all windows updates (SP2, etc.)
Initially I thought this might be due to my old video card's fan failing, so I purchased an ASUS EAH2400 Pro (Radeon) PCI-Express with passive cooling. This gave me more problems as windows was taking forever to startup or shutdown, and sound was all choppy too. The crashes were much more frequent with the new video card installed.
I've replaced the EAH2400 Pro with an nVidia 8500GT (by XFX) also PCI-e with passive cooling. The drivers seem better (Windows starts/shutsdown much faster and audio, etc. seem to be working fine) but I still get random system resets.
I've run Memtestx86 overnight previously and it did not find any errors. I've tried changing the slots of all 4 dimms in the system. No difference. My BIOS was showing my 5v was low (around 4.45v). I've just installed a new (albeit noisy) 500W PSU and the voltage is much better, but am still getting random lockups.
Cooling is not an issue, my P4 3.2 Prescott is running at <50 C according to speedfan.
Things are definitely worse when I install my video drivers, but I can use them and run at a low resolution (say less than 1280x1024) for a while with no problems. If I crank up the resolution to 1920x1200 the screen/system freezes instantly. Without the drivers installed, I've had a few lockups/reboots though much less frequently, and it seems the system is almost useable.
Please note that I'm not a gamer and I only have been running 2d apps. This system is almost 3 years old and has been running perfectly for that long. This fresh install of windows has nothing on it except speedfan, Avast antivirus and Microsoft updates.
Any help or suggestions would be gratefully appreciated as I'm at my wits end and have spent a fair chunk of change on new hardware, all with no improvement.
My system info:
Motherboard: ASUS P5GD2 Deluxe w/ BIOS 1007
CPU: Intel P4 540 (prescott 3.2GHz) NOT overclocked
RAM: 2 GB DDR2 (4x512MB; 1G each for two brands: Samsung and OC)
Video: XFX nVidia 8500GT passive