step 1. Run anti virus scans (below are links to two free online scans)
Panda Activescan
Trendmicro Housecall
step 2. Run adware/spyware programmes (below are links to two free programmes, downlaod/install and run them)
Adaware SE Personal
Spybot Search and Destroy
If you are running XP you may need to remove your restore points if they are infected, to do this follow these instructions.
start > all programs > accessories > system tools > system restore > disable system restore. Once you have disabled system restore the existing restore points will be removed. *Dont forget to re enable system restore once you have done this*