Rootkit scan stops after a second or two, says "scanning was interrupted"
My email program seems to be sending out spam to people in my address book once every week or so. I've run a full system scan of my Windows 7 Home Premium PC, but it doesn't find anything. When I try to run an F-Secure rootkit scan, it starts but then stops after about 1 to 2 seconds, and displays the message "Scanning was interrupted." It also shows that 0 items have been scanned. I'm worried a virus/rootkit is preventing F-Secure from running properly. Is there a way to force a rootkit scan to run, or to determine what's infecting my Windows mail?