Did you reinstall your video drivers? Make sure you've done that, then go to Control Panel\Display\Settings to adjust things.
I had a crash and had to reinstall everything. I installed a program called Galaxy of Mahjongg (cannot contact owner) and after playing it once, my wallpaper and screensaver (and everything else)looks like I am running in Safe Mode. I updated Direct X, but that didn't help. Oddly enough, the program that caused the problem has beautiful colors.