a few days ago i was running my computer perfectly fine.. after a few days i started noticing these lines (short horizontal lines ..multi colored-ish).. soon the problem grew worse and my whole desktop would be filled with these lines and i wouldn't be able to access any part of my computer. now today, i booted up my pc like normal and right when it hits the "welcome" screen in windows xp, the lines show up again and my computer sort of locks up, except that you can move the mouse a bit with major lag as it moves. i tried reformatting and the problem came again right when i installed my video drivers (i installed nvidia drivers for my geforce4 ti4200 and ATI RAGE 128 PRO, both had the same result) so now my computer can't get past the welcome screen and i can't use it at all except for safe mode. ahh i'm confused since the computer has been running fine for 2 months but it suddenly dies on me.. anyone have suggestions to fix this problem? thanks

When in safe mode ,right click on mycomputer and go to properties /hardware /device manager ,Hitting the + by display Adapters ,and uninstall you video drivers and reboot letting xp install the video again .
Sounds like a bad video card or Monitor

hmm but when i took the video card to another pc it seemed to work fine... or does the computer need to stay on longer till it experiences problems like on my pc?

It might be a bad or corrupted installation of the display card drivers that is causing the problem. The procedure outlined by caperjack could correct the problem.

In actual fact, since you've mentioned both an NVidia card AND an ATi Rage Pro card, I rather think that it's leftovers from previous driver installations that might be causing your problem. It's not really a good idea to change cards from one brand of graphics processor (NVidia) to another (ATi) without starting over. Simply changing drivers doesn't always do a good job, and bits of the previous drivers get left behind to cause problems.

In your situation I'd format and install Windows again fresh, to see if the card works properly on a fresh install

ok i reformated the entire computer and installed the nvidia drivers again, same thing happens - so after that i reformat AGAIN (something went wrong and my computer kept freezing) but with the use of my brothers g4 video card. everything works now so i'm thinking that my g4 ti4200 died on me?

Sounds like it, Syusuke. I've successfully 'resurrected' a seemingly dead GF4Ti 4200 before by removing the heatsink/fan and fitting a CrystalOrb heatsink/fan to it, but it's a fiddly job and not one for beginners. There's no guarantee of success either.

Looks like it's time for a new display card, eh?

hehehe replacing the heatsink sounds hard.. so i guess i'll go get a new one, thanks for all the help guys!

-Syusuke