xp os wont load

Ok so a few days ago i was on the supraforums and i clicked a link for a video and then all of a sudden my screen gets lines in it and it freezes then trys to reboot my computer. so it does that for a few days every time i try to play a game or watch videos. now i tried to reinstall some other drivers on my nvidia geforce 5200 card. but that didnt work. i tried a digitally signed vers of them on my computer and it would do the same thing. then i tried ones that werent digitally signed and now my computer wont boot back up. i get to the windows loading screen and it go past it to a black screen and just sits there. whats the deal? any help would be great. thanks

Adam