What is the make and model number of your computer?
Edit: Also, you could try updating to Internet Explorer 7. It worked well for me on my old HP 750C system where IE8 would not run well at all.
It would also be worth trying a different browser, like Firefox, Opera or even Google Chrome just to see if the problem occurs there as well.
Edited by Ztruker, 26 October 2009 - 12:53 PM.