Can't connect to BE server

Hi all :)

Odd problem has just cropped up. All of a sudden when I try to open BE 2012 (on the actual BE server) it asks for logon credentials.

Nothing has changed regarding this and when I type in the appropriate creds I then get a "could not connect to server" error and under additional info it says that the BE management service was unable to start... although it and all the BE services are started.

Anyone know what might be causing this?

thanks

Tracy