What version are you running? Check here if yours is compatible.

 

http://www.iexbeta.com/wiki/index.php/Windows_Vista_Software_Compatibility_List

i ahve recently done the dell vista upgrade and hadsome problem of my own. i sugest to uninstall msmn messenger and try downloading msn live just type msn live into google you shoudl be able to find this, once you have downbloaded in stall it that should work i hp ethe information i have given you has been of your help.

After you install Vista you get Windows Live Messenger to download in your start menu click on it and follow the setup steps. Windows Live Messenger 8.1 is the latest edition available.