A whole string of numbered tasks triggering a randomly-named 16-bit .com program hourly are an odd thing to see in Vista or 7. I second the above advice. Thoroughly.
Update: the OP has a virus. He is a member of a botnet. The tasks with sequential numbers - at1, at2, at3, etc are a clear sign of the conficker virus. If the infected computer is on a network, the OP should contact the system administrator URGENTLY to get all connected machines disconnected and disinfected. If this is a standalone machine, post again in the Computerhope virus/malware section, or whatever, but do something SOON.