System Freezing

Just want peoples' views here to my Issue.  Just yesterday - Tuesday, November 04, 2008 - when I have Internet Explorer open, all of a sudden, my computer would freeze-up and when I tried to click on most Web Links, the Page would not Load-up.  Even today when it happened, when I clicked on Norton LiveUpdate, it would not Load and had to press the Power Button to Turn Off the computer and Turn On again.  I have Scanned in Safe Mode - Full System Scan - with Updated Virus Definitions with Norton and a Quick Scan with Updated V.D.s with Malwarebytes' Anti-Malware and not picked-up anything.  Could I be Infected - nothing has been Detected - or could it be Norton-related?

 

 

N.I.S. 2009

Windows X.P., S.P. 03