I downloeded the new msn my cam stoped working i

Test your webcam here to make sure it broadcasts OK - Hit 'Allow' in the top window and check your cam in the left hand panel.

http://www.testmycam.com/

Having proved your cam is working ,you can configure it to WLM (MSN)

CONFIGURE SOFTWARE to MSN
Its good practice to disconnect and re-connect your webcam before you start - if you have been using it elsewhere the MSN software may have difficulty in locating it, even if you exited the previous program correctly.
The reason being, the webcam software can remain hooked-up to a program and needs to be rebooted.
Mine, I just unplug it from the USB and plug it back in to reboot the software.
If yours is integral with the computer you will have to re-start the computer, use a keyboard shortcut or disable / enable the webcam from the Device Manager.

Open MSN
Click 'Open Menu'
From 'Tools', navigate to, and click, 'Audio and Video setup'
Set your speakers
Click 'Test' - if OK, move on.
Set your mic as default
Use the slider to set volume and test.
Click 'Next'
This takes you to the video setup
Your webcam should be broadcasting - if not - make sure the webcam is set as default - restart MSN
Use 'Webcam Settings'to fine tune the picture.
Click 'Finish'