Runtime Error

I log onto MSN Premium (and automatically to MSN Messenger) and I get an error message saying “Runtime Error:Application has requested Runtime to terminate it in an unusual way” (no codes), and will not let me sign into Messenger. I’ve had many e-mail discussions with MSN and tried many different suggestions. I’ve re-installed MSN Premium and Messenger, still no cure. Messenger Tech support suggested re-installing the operating system ! I’m not quite that desperate, just yet. Once in a great while it lets me in. Most of the time the butterfly just sits there and spins. Sometimes I try to log-in, type my password and hit OK and the password defaults to some other password. I know this because it has less characters. Any suggestions ?