If you have only just got it in the last couple days shut off system restore (right click "my computer" then "properties" then " system restore") then go to "start" "programs" "accessories" "system tools" "system restore" and restore your computer to a few days ago, then when the computer restarts if everything looks ok turn your system restore back on (right click "my computer" then "properties" then " system restore")

Run your virus scanner again to check everything is ok.