Well, the subject pretty much says it all... About a month ago I finally upgraded Windows XP from SP2 to SP3 on both of my pc's. Ever since then my weekly Full System Scan times have increased from 30 minutes to 50 minutes on one of the pc's; and from 50 minutes to 90 minutes on the other. 
I assume SP3 added some new files, but not enough to account for scan-time jumps of this magnitude. Has anyone else experienced the same situation and/or have any ideas on what may have happened and how to remedy it (if possible)?
Thanks.