Don't go for Avast please. If you are willing to pay then choose Kaspersky or Symantec (i prefer Kaspersky). If you want something free please go for the microsoft AV, it better then AVG and avast.

Update, Update and Update - Everything on your machine and the OS itself.


Run a online scan at housecall.trendmicro.com once you're done with everything just to be sure.