AVG free is a good free anti-virus. Avast is ok too.
Also - Microsoft Antispyware gives you real time protection against spyware - and is currently free (in beta, but works very well).
i think i have a virus or spyware . i use Spy Sweeper
.Ad-Aware SE Personal .Spybot Search & Destroy CCleaner.but something is stell runing in the back ground.i have no virus programs do any one no any free virus programs.