You did not mention any corrupted displays(e.g. random bits or blocks of color or random lines) or scrambled displays or improper displays. Your symptoms don't particularly point to any problem with your video card. You could try cleaning it's contacts and making sure the card is properly seated, but I doubt you have a problem with that.
"When I try to install XP, I usually get unnamed BSODs."
Is your Windows XP CD scratched?
It is a copy of a Windows CD? - if it is, is it a CD-RW one? - if it is some CD drives have problems reading a CD-RW - make a CD-R disk for the most chance of no reading errors.
Have you tried cleaning the CD, cleaning the laser lens on the CD drive?
If you have more than one CD drive, have you tried the XP CD in a different drive?
"If XP installs by some miracle, i get frequent BSODs. Both "nv4_disp.dll" and "memory address" errors."
Have you made any changes to what ram is installed in your computer since it last worked properly? If you have, install the ram that was in it when it last worked properly if you can, or try the modules one at a time.
Have you tried cleaning the contacts on your ram modules?
Have you tried testing the ram with something such as memtest86?
If you get errors, try the modules one at a time. A module that fails isn't necessarily and often isn't bad - it may just be incompatible with your particular mboard.
"With Windows 2000, I get no BSODs, but games will lock up within seconds or minutes of running. Windows otherwise runs fine."
Have you tested the hard drive with a manufacturer's diagnostic utility(ies)?
Have you checked out your PS - a failing or faulty PS is common, and can cause all sorts of weird symptoms.
Check your PS.
See response 4 in this:
http://www.computing.net/hardware/w...
If you loaded a bios update......
After you flash the bios, the first time you boot you will get a "Cmos Checksum Error...." or similar message. You will either be prompted to enter the bios Setup or you will automatically go there. Enter the bios Setup, and load Bios Defaults (of any kind) - save settings, reboot. You MUST do this (or Clear the CMOS by moving a jumper on the mboard) in order for the bios update to be fully accepted by the mboard.
Loading Defaults may work in situations where Clear Cmos does not help.
You might as well correct the time and date while you're there (you may get the Cmos Checksum error or simlar again at the next boot if you don't), or you can do that in Windows.
If you have AGP video, after you flash the bios make sure your AGP video is enabled in the bios, has been assigned an IRQ if that setting is there, and AGP video is initialized first - if those are set to PCI, on some systems you will have no video once Windows starts to load.
If you have a fairly recent model scanner or printer connected to a parallel (LPTx) port, you also need to make sure it is set to EPP, EPP/ECP, or ECP mode in the bios - usually EPP is fine - ECP mode also requires you use Add Hardware in Windows to install an ECP port if it is not already there in Device Manager.
