Goto Start->Run-> and type in “gpedit.msc”
-Computer Configuration
-Administrative Templates
-Windows Components
-Windows Messenger
Here you can enable
“Do not allow Windows Messenger to be run”
and
“Do not automatically start Windows Messenger initially”
You can also use this to limit the bandwidth the background intelligent transfer serverice (BITS) uses. This service is what controls Windows Update. You can use this to only have it use a small portion of your bandwidth, so you can use the rest.
gpedit.msc –>computer configuration–> Administrative templates–> Network–> Background Intelligent Transfer Service
This allows you to even specify certain times when bandwidth consumption should be low, for when you’re on your computer, and when it can be high.