I've never used it to be honest.
AdAware has always been my utility of choice to get rid of malicious software. Whilst I'm not personally up to date with these programmes as I haven't used Windows for a while, Ad-Aware still seems to get the job done with no fuss when I've used it on other computers.
It's probably worth giving it the once-over with a virus checker too - AVG or Avast are both decent free ones.