I'm not sure whether I am allowed to ask for help in this way, but I don't really know what to do and everyone seems so helpful on here.
Over the last few days I've noticed my computer has been acting strangely, in particular when I use Google. When I do a search and click on one of the results it opens up in a new window (whereas before the window I was on just re-loaded. I've checked in the preferences section and the box is unticked for this option anyway). I'm guessing something (virus?) has made it's way in somehow. I've been scanning my pc with AVG (free) anyway, and some stuff that came up were some cookies (tracking cookie:Tradedoubler, Doubleclick, Admarketplace, Yieldmanager etc) . I've also noticed the same (dodgy) ad appearing on different sites, as if this 'thing' is able to replace exisitng ads. I've checked the installed programmes and nothing looks out of the ordinary there.
Can anyone shed some light as to what is happening, plus suggest a solution to stop this happening?
All suggestions would be very gratefully received.