Internet being used?

I am running my pc, with nothing else that should be using the internet, yet on TBB netmeter it is showing a steady usage of around 600-700Kbps upload with no download.

I have run spybot S&D, I have Bitdefender 2010 running on my system and everything is up to date.

Any ideas on how to find out whats going on? I did trawl through some webpages and found Netlmiiter but this doesnt seem to be working too well on W7.

Hope someone can help, as it is slightly worrying thinking why that bandwidth is being used, btw no p2p running, and I have looked on task manager at running processes and cannot see anything untoward in their either.

Managed to get Netlimiter working after running in XP compatibility mode and also downloading the 64 bit, it was Xfire (a gaming msn messenger) I was downloading the new 1.6 patch for COD WAW, it must utilise p2p via that so you share the patch too, anyway, restricted my upload limit now, so it's sorted!