I'm running XP on my computer, which starts up fine until it gets to the login screen, when it becomes 800 X 600 resolution and 4 bit colours. I can log in fine, but can't change the PROPERTIES to a higher resolution. I recently put in a new grahics card, but that was working fine. Whats going on? How do I change it back to normal?Reinstall your video drivers and see if that helps.Did this happen before the new video card?I tried reinstalling the card drivers then restarting, but that didnt work and no its only happened after I put the graphics card in. But it was working fine for a while. Its needed a new processor for ages and I was wondering if perhaps it couldnt cope with higher resolutions and is reverting back to something it can handle. Is that possible and would a new processor fix it?What is the new video card you put in?

Did you uninstall all instances of your old and new video card,
then install the drivers for the new one you added?When my card died my computer would start the same way, sometimes, the other TIMES it would BOOT to nothing but a black monitor.

Your card could possibly be a dud (it happens to everyone at one time or ANOTHER).

I cant see how the processor could do this so its replacement is a purely optional thing.If your computer could handle the resolution fine with the old graphics card but the same processor, then the processor is not an issue.

When you go to the Welcome screen you say the resolution and colour depth is fine? In display properties, try looking in advanced > monitor and unticking only display settings this monitor can do or whatever it says. Ok that then look on your display properties again.are you in safe mode