I am an amateur. So there is nothing simple I should know.
Basically, I installed Linux on a my PC as windows 7 kept freezing just to give something a try. It worked. So my brother made me make him an account and it never worked. It is always leaving a black screen that required a hard crash. Then (after an infinite amount of complaints to parents) I tried to fix the problem and accidentally turned auto-login on his account and now Ubuntu boots straight to a black screen.
I've tried stopping auto-login, deleting his user, adding a password to it and several other things has given no success.
Any ideas please?
Thanks in advance (for trying).