Hi Feckit - you're an Angry Bird-er aren't you...? (If I'm mistaken, then apologies.) However, looking around, quite a few folk who have Angry Birds installed, seem to be experiencing the same thing as you are.
Someone has found a solution here: Win7 Forums and there are a couple more suggestions on here: Angry Birds nest which also seem to have solved it.
Cheers TC, yes i'm into Angry Birds pc games (got the star wars one for xmas!).
Had looked on the net before posting & it seem to be a problem but not a nasty!