I cannot see how just unhiding hidden files would do this. I frequently change the hidden files setting (unhiding and later hiding) in the manner described in the posting in your link and never have any issues.
It sounds to me like you have either inadvertently clicked on a delete buuton instead or there is (and was) something fundamentally corrupt about your installation.
Unless you have a backup that you can restore I'm not sure that you can readily recover (especially it is not clear as to the extent as to what has been lost).
Maybe the best you can do is create another user on your PC and use that as a clean start. But I suggest you wait and see what suggestions others might come up with.