AIM problems please help

ok i got a b/list on 1 sn of my 3 the ones without /i just made work perfectly fine the 1 with my buddys which ive had for liek 3 years now wont let me log into it i press sign in the window disappears and the icon on the bottom right is still there saying sign in but it wont do anything the only way i can get the screen back is if i exit the program and reopen it which it comes back to the sign in screen my other 2 screen names work fine i cna sign it and all that its just this 1 can any 1 help me ill give u all the info on the screen name if u need to see for urself if u have an answer try to email me at [email protected] if not here will be ok