I'm not going to get too excited just yet... but I believe that I've found the monster and disabled it!
First I located Microsoft Security Essentials, I had already disabled it, but I completely removed it from my computer and wiped the remnants with Revo Uninstaller and CClean.
Then I did the following:
services - Windows Update (wuauserv) Startup Type set to: Disabled
Stop The Service... Then set it to Disabled.
Yesterday after I set this up, I logged on to the Internet and was connected for 4:53:39 sec and used only 26.6 MB of DATA! I'm using Windows 7 Home Premium. Today it has been the same results so far... I've been connected for 58:58 sec and I've used only 4.2 MB and I'm still connected.
Go to your services and locate this service, click on it and read the info in the left hand box or double click the service and read it all it pop-up, Let me know your results.