Seems like this is a little tricky. Try these directions:
1) Select MSN Content Plus program and click <Remove> button to uninstall the program.
2) After uninstall and reboot system, the Register alert should be removed.
3) Press F8 when windows starts up and enter safe mode. Find and delete msnappm.foo in the system directory. (Either in C:\Windows\System or C:\Windows\System32)
