My msn wont work?

when i sign in on msn live , it signs me in , and as soon as it signs in and it gives me this message ' Windows Live Messenger has encountered a problem and needs to close. We are sorry for the inconvenience. If you were in the middle of somethink . the information you were working on might be lost.
Please tell microsoft about this problem ' and it comes up with these to choices ' send error report ' or ' dont send ' and either one we pick it closes msn down anybody know why?
Answer please .
Rosiie