Time for you to run some malware scans. http://www.makeuseof.com/tag/10-free-online-malware-and-virus-scanners/ . Install Spybot as suggested and do the Immunize thing.
I think the ultimate cause of this was that you probably invited it onboard. i.e., it wasn't some virus payload. You need to be real careful when installing apps. I think you're running Win7 now? That's good, but add more protection by running a limited user account, and keep UAC set fairly high. PS pwn is pronounced "pone" rhymes with "bone". Or pwned "poned" rhymes with and means "owned". Like a few others (zomg!), presumably started from fast typing with the o and p keys being switched. ************************************************************************* ** List info, subscription management, list rules, archives, privacy ** ** policy, calmness, a member map, and more at http://www.cguys.org/ ** *************************************************************************