restart the computer,keep pressing F8, you will get a menu,choose SAFE MODe. your computer will start in safe mode. your colors might be kinda fucked,but thats because its in safe mode. run virus scan from there. it should get rid of it. when ur done rastart the pc, and it should be back to normal.
before u boot into safe mode and run virus scan,make sure you have msn uninstalled. after u delete the virus,then install msn back