Why we are Unable to see Dashboard!!??

We have many sites built in wordpress. Nowadays we have been facing a problem in all since the hosting company suspended them just cos of comment spam. Problem is we are unable to see the dashboard as it shows site and gray dashboard bar. Dashboard bar is there that means I logged in successfully but cannot see dashboard.
We installed one more wordspress in a sub directory, configured it and then tried to login to see the dashboard and it is all there.
very strange why we cannot see the dashboard thoroughly on main site.

Please help.