In order to resolve this problem, you can try to go to Start > Run > type cmd and press Enter > in the command line type regedit and press Enter. A new window will open, and you can try to go to:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon\
and delete GinaDLL with value athgina.dll. This should fix your problem. Also, you can try to use a third party software to delete the file or quarantine it. I suggest you visit Software Informer in order to find and download a tool that can help you with this job.