Webroot Antivirus with Spy Sweeper 2011 makes Vista freeze?

I did work on a computer this morning that was freezing 2-4 times per daily; usually when the screensaver was active.  The freeze was a total screen and mouse freeze, in which the power button needed to be held in.  It is a Dell Inspiron tower with Vista SP2 32-bit.  I looked in the event log and found that the freezing began almost immediately after Webroot Antivirus w/Spy Sweeper updated to version 7 (2011 is the marketing name).inFOLIO Research Group

I uninstalled Webroot and installed Microsoft Security Essentials temporarily to see what happens.  Please comment here if you are having similar experiences.