NIS 2011 Freezes Computer

I am running Windows XP SP3.  I am having an issue with NIS 2011 not being able to complete a full scan.  Part way into either a manual full or a idle full scan the computer will freeze and not respond to anything and I must do a cold boot.  Sometimes I belive the computer reboots itself as well.  I have read through a few posts here and will try the fixes.  I do not really see any error in event viewer that is related and need a little trouble shooting help.  If all else fails I may just use a back up image of right before I WAS able to do a complete scan. 

 

I am not sure if this is related but since the last time I was able to do a full scan the following has changed: I tried to install Abobe Reader 10 and it failed many times so I installed Foxit Reader 5 (Now uninstalled) and had to settle with Adobe Reader 9.  I also installed Windows Updates KB (2555917) & KB (2507938).  Plus I think there was a NIS update that required a reboot.  I am not sure if any of this is related but wanted to give as much info as possible.  This is not my primary PC so I don't use it that much plus I was on vacation so the last time I was able to do a full scan was July 5th, 2011.