Do you run Adaware or any spyware checker on it?
I had a similar problem and that is what it was..

http://www.lavasoftusa.com/ (this is for adaware
download...just click on the download button and
it will take you to the page to download it..its
free)

I run several to check my system...here are some
more free ones...

http://www.pandasoftware.com/activescan/com/

http://housecall.trendmicro.com/hous...start_corp.asp

Try these and see if they help k? Let me know...