Try these methods.
1. Open windows Task Manager: Ctrl/Alt/Del then click on Processes. Stop all instances of IM-SVR.EXE by right clicking and selecting STOP. Close the task manager. Click on Start/Search. Search for im-svr. Delete all entries. If that doesn't work then try:
2.
http://www.stiggy.be/msn/index.php/IM-Names(Malware)
This involves editing the registry but is fairly straightforward.
Good Luck.