I am running DNN 6.01.04 Community.  I upgrade about 2 months ago.  One of my users tried to log in a few days ago and was unable to.  She enters username and password, clicks login and nothing happens.  I tried to edit her user account: admin>user accounts, and when the pop up tries to load, it says 'internet explorer cannot display the webpage", I have the same response with host>user accounts.  I've since found that the only accounts that can login are the host and admin accounts, also when a new user tries to register, the register page is loaded, but the form is not there. 

I've tried to find this exact problem on forums with no success.  Any suggestions?

After disabling compression, I attempted to edit a user account and was presented with this error :

Exception Details: System.IO.FileNotFoundException: Could not load file or assembly 'Active.Modules.Social' or one of its dependencies. The system cannot find the file specified.

I had active social installed, and removed it because my site was being continually hacked with a url redirect. After removing the module, I have had no hacking problems.

Obviously I need to change something here to get the site using the default login and registration. Suggestions?