Hi Gabriel,
Looks to me like something has gone seriously wrong with your upgrade. It happens, but rarely. Frankly, I see no other solution than to start with a Clean Install, but you might want to wait until others have had a chance to respond.
If you have never done this before, do read up on it, there are plenty of posts available on how to do this, but do post if I can be of any help.
Regards,
Stephen