I think it is "Spy Sheriff -- a known fraud from the Philippines somewhere. A bitch to get rid of -- but it can be done effectively. Best best search Google for "Sprware Sheriff" and follow recent links or promising titles. Exp[ect to see forum threads like THIS:
http://www.spywaredb.com/remove-spy-sheriff/

Perhaps your virus/malware checker utility has a routine to easily find and get rid of it -- but mine did not.