I'm stumped on this (other than admitting that my video card is dying). I have an EVGA Nvidia GeForce 7600GT video card running on an XP Home SP3 PC. It has worked fine for 3 years with no complaints. Last week, I rebooted my PC and it came up with display settings of 800x600 and 4 bit color. System Restore didn't work. Instead of reinstalling my video drivers, I used my old FixIt Utilities recovery commander program (which has worked a few times before when System Restore failed) to recover my system to the day before. Well, that little gem damaged my boot sector and my hard drive disappeared.
Having kept good backups of the important stuff, I wasn't too worried and just did a format and reinstall of Windows. I finished the install and fully updated Windows 2 days ago. No problems over the last 2 days. Today, I do the following:
Playing CNC3: Tiberium Wars and I get a BSOD with nv4_disp.dll being listed as the cause. I had this same thing happen 2 or 3 weeks ago and downloaded a new nv4_disp.dll from dll-files.com. It fixed my problem back then and I never saw the BSOD again until today. So, today I do the same thing with that .dll file. I restart the game and play for about an hour with no BSOD. Afterwards, I rebooted and got the 4 bit color display. I go back into the System32 folder and rename the original .dll file back to the way it was so I have the first nv4_disp.dll file in place. Reboot and still have 4 bit color.
Next, I stick my video card CD in and uninstall the drivers. Windows reboots and I have a perfectly good display with 6 resolution settings and 32 bit colors. I reinstall the Nvidia software from the CD (just like I did 2 days ago with the OS reinstall) and reboot. BACK TO 4 BIT COLORS AGAIN!!!
Uninstall the drivers again and reboot. I get 6 settings and 32 bit color again without the drivers. So, I let Windows find and install the proper drivers from the internet this time. Reboot and I'm back to 4 bit colors AGAIN.
If I install my video card drivers, I get childish 4 bit color resolution from 1982. If I don't have any video drivers installed, I get usable graphics (albeit, sluggish graphics) as long as I don't do any gaming whatsoever.
Can anyone help me with this? I've googled here and there but have found no one that has had the same issue.