Below is my guide on how to protect your computer from dangerous viruses circulating Msn.
Step 1.
Open up Msn, and go Tools->Options.
Step 2.
Scroll down the list of titles that appears on the left side of the screen and click on 'File Transfers'.
Step 3.
Tick the box that says 'Automatically reject file transfersfor known unsafe file types. Then press 'Apply' at the bottom of the screen.
This should automatically cancel any incoming file transfers were there is a high chance of them containing a virus.
If this guide was of any help to you, or somebody else.. +rep me baby.