Starting a few days ago, when I boot up XP Home, my desktop screen is so messed up and unreadable that I'm unable to do anything else. (Too many horizontal lines.) If I reboot, using VGA mode, everything is fine and I can proceed as normal. When I check screen settings (after using VGA mode) they show 800x600, 32-bit color, 75Hz refresh, which are the normal settings I use for my Nvidia card; I have the latest driver. Device manager shows the monitor and display adaptor to be working OK. I have uninstalled and reinstalled the driver, with no change. The registry indicates that the nvidia is set to load first, but I have no way to log and read the startup routine, since my normal boot screen is not readable. Unfortunately I don't have a system restore point before the problem began. How can I get back to a normal boot?

So I don't quite get "after using vga mode". After using vga mode upon next bootup your screen appears normal? This sounds to me like you have some memory on the video card is going bad. Or its your monitor not accepting the refresh rate of 75hz. After all the driver and everything else is the same when it works and when it doesn't, right? So swap the monitor with one you know supports 75+hz to start and swap the video card for second.

The only way I can successfully boot to a readable screen is to enable VGA mode during the boot process. However, once I've done that, I can change display settings to any mode my monitor accepts, up to 85Hz. The system works as it should, but only after booting via VGA mode.