Headset problem

[bpizzle1]

So i just got a new motherboard and case. Im currently using the realtek 7.1 built-in sound and everything sounds just fine through my speakers. however, when i plug in my headset, i can hear this high pitched squealing sound through my headphones, and according to people on the other end of ventrilo, they hear a similar sound when i talk. i know its not just my headset because i plugged in another set of headphones that i had sitting around and i get the same noise. the noise is very electrical sounding and it seems to coincide with my cpu processing (ie gets louder when i open up things/ scroll webpages etc). anyone have any ideas what could be causing the problem? id really like to get this solved as soon as possible because its the most damn annoying sound ive ever heard lol.

ps. after i installed the latest drivers last night, the noise disappeared, but as of tonight it suddenly came back. reinstallation of the drivers did nothing to fix it this time.