Wow, insects on the screen and all? That sucks. I would just try every anti virus known to man, and if that doesn't work, back up your important files and reinstall Windows.
A fresh Windows reformat feels nice every once in a while anyway.
LEFT4DEAD411.COM
Bet with disolitude: Left4Dead will have a higher Metacritic rating than Project Origin, 3 months after the second game's release. (hasn't been 3 months but it looks like I won :-p )