Block Unwanted popups

I have a terrible problem. Some spyware has got into my computer. Inspite of putting google pop up blocker on high, pop ups still come on. One is on online gambling, another is a site called pcturbo which keeps interfering with any page that I am looking at, another is on window optimisation or some such thing.

I tried cleaning my PC with CCleaner and run adaware also regularly. But both are not effective. Since my mcfee expired I downloaded AVG antivirus about a week back. I am not sure if these pop ups came along with that.

Please let me know how I can block these irritating pop ups. Thanks in advance for your help.

Regards
Samdias