Windows Live Messenger Error 81000306 on Vista

Ran into a problem where a Vista machine joined to our corporate domain would not allow you to logon to Live Messenger. If the same machine was taken outside the office it would connect without problem. SO after searching and searching, upgrading to the Beta 8.1 (Still did not work), found a solution that worked.

Try this:
- Click start
- Type: cmd
- Right-click cmd.exe when it appears under Applications
- Click Run As Administrator
- Type the following: netsh int tcp set global autotuninglevel=disabled
- Press enter
- Restart your computer

To check autotuning is disabled repeat the above but type: netsh int tcp
show global

This worked for me when all other fixes and work-arounds did not.

Hope it helps someone else!