Whenever I attempt to watch a video online (Hulu in particular, among others) my computer suddenly locks up. I do not receive a blue screen, what happens is my computer loses responsiveness to mouse and keyboard input and all graphics stop entirely. I can still hear sound but it sounds as if it has been slowed down to a fraction of the normal speed and gets high pitched robotic static sound garbled in. I've tried reinstalling macromedia and java in hopes that it may solve the problem and I've even gone so FAR as to reinstall mozilla FIREFOX (my primary browser) and test INTERNET Explorer, getting the same results from IE. I installed a new graphics card back in June but this problem only recently occurred a month ago.This is similar to a problem I had with my 9500 GT graphics card. For a few months everything was fine, but then it started to lock up when watching flash video. At first, I was able to close out of the browser and regain control, but after a few more days it WOULD lock up for about a minute and then the BSOD would come up. I ended up RMAing the card, and the replacement has been working fine for about a month now.

Do you have another graphics card that you could put in to test if it solves the problem?