The reality of AV software is that a lot of people have problems with a lot of it, with all kinds of weird effects on certain application programs, or aspects of Windoze operation.
Norton/Symantec works most of the time, and really messes up the PC for some people. As does McAfee.
I now use Kaspersky everywhere - it works best. The Personal Pro is the one to go for; the Personal only has no options for excluding folders from being scanned. It's an excellent clean program which does what it should.
Russian programmers are the best today
Forget America - the best people they had went off surfing 10 years ago.