Vista - World of warcraft problems - fps randomly dropping.

Hello, i am new here and i think this is the right place for this post.

Ive been playing warcraft for few years now, i got a new computer with the current spec ive posted on my profile around a year ago. I have done many system restores and what not since ive had it and lost a fair amount of the drivers i got when i bought it from dell, ive had a new motherbored case installed since i got it from dell (bios died on me), recently (within 2-3 weeks), i will be playing and my whole systems performance will drop epicly at first i thought it could be my sound card, well still think it might but was wondering if anyone has and problems like this before, i usually have about 30-40fps running with high graphics on but ive had them all on low recently and still every now and then it will drop to about 2-3fps.

Thanks for you time

~Patto

this may sound like a stupid question , but if you minimise the game then maximise it again does it sort out the FPS? What GPU? what drivers are you running?