Msn Messenger shuts down after login

I have MSN Messenger 6.2 and Windows Messenger 5.0 installed.

In the last two days, when I go to login to MSN Messenger, it logs in, then
disappears. I can use the id and password on other PC's.

I have already deleted the messenger folder and tried reinstalling both
Windows Messenger and MSN Messenger.

Some differences. I upgraded the firmware on my d-link router and added
extra memory to the pc.

This is really bugging me.

Any hints?