I'm having the same SiteAdvisor pop-up problem - got to work fast with my fingers to get around it! Anyway, it's not listed in the "Add or Remove Programs" area, and when I open Security Center and click the 'about' button, I see that it was updated 12/31/1969. Yep, you read it right.
Problems started last night around 11:00 p.m. when I watched McAfee wipe out all my games, some were Big Fish and some weren't. I was able to run System Restore, but bungled that by not disallowing updates, went through the same thing again. Now I am unable to run the System Restore Wizard at all - says it's unable to restore anything.
My questions are: How do I get rid of Site Advisor altogether? How do I stop automatic updates? And, more importantly, how do I get my games back???? They're all still quarantined . . .