blank admin page

I logged into the admin panel tp update my blog. There was a message that there was a new wordpress update. I clicked update automatically. Things seemed to go well until I tried to log back in to edit my blog. When I go to PHP-Login I put in my username and password but I am taken to a blank page. Does anyone know what my problem is and how to correct it? I just tried repairing the database but that didn’t help.
Thanks aggie