I cant login to my pc.

Ok, so a few weeks ago, i got my gaming pc. Its the asus rog g20 by the way. I tried to play terraria, didnt work. I looked up how to fix it and it said reinstall .net and .xna. I did that, the day after, i couldnt login. Everything starts up, i get to the screen where i enter my password (and i know its right, i never changed it before,) and when i enter it, it says welcome... black screen for a few seconds and then i get thrown back to the screen where it displays the time. If anyone can help, i would really appreciate it.
Thanks.

from Windows Central Forums http://ift.tt/2gGhMIT
via IFTTT