popups like system integrity scan wizard

Hi
I am very keen to get rid of a problem i ahve had for over a week now. if anyone can help, id be very grateful.

My machine appears to be infected with a spyware causing a number of different popups claiming System integrity Scan wizard and linking to a web site for PCantispyware, and also alerting me about a trojandownloader.XS wanting me to click and purchase anti virus . Also a system warning abopout Adebot virus.

i have tried a number of things like safemode scans, installing ad aware , rogue remover, pc spyware doctor etc but popups persisting.
whre to from here ?

Down under and desperate!