[Typo3] Cant login to BackEnd

[Gediminas Bytautas]

Hi all, 
I have searched for an answer all around the net and in old mailing lists, but still
can't find an answer to this. While insalling BackendModules I timed out my connection
and had to re-login but when I refreshed a login page I did get a "Version not
detected!" in top left corner and a blank page. Is there a way to reset to an old login
so I could login? I don't know which plugin causes this, because I installed at least
couple of them. I have a direct access to a Linux server. Front End works fine.

Regards, Gediminas