The only way to fix the process is by re-installing the application. The official support information states that a clean installation is required. To proceed, simply uninstall the application and then answer NO when you're asked if you want to delete the data. This way you will preserve the custom settings, apps, etc.
After the uninstallation, go to Start > Run and type regedit. Navigate to
HKEY_CURRENT_USER\Software\Bluestacks. Right click it and delete it, then reboot the computer and re-install Bluestacks through the application's page at Software Informer and it should work normally afterwards.