A friend of mine recently upgraded to windows 10 but was having a few issues so decided to revert to windows 7. However upon doing so can no longer access his pc unless it is in safe mode. When trying normally he tries to put in his password but comes up like this "The group policy client service failed the logon. Access is denied". Entering safe mode works and we have tried going back to a recovery point but the only one available does not fix the issue. Our last option is to reinstall windows completely. Is there anything else we can do before we try this?