Windows 7 crashed now not accepting password

[CurryPls]

Hi, my brother was browsing YouTube when his PC came up with "Windows has crashed", he can't remember whether or not it was Windows Explorer or anything to that effect, but it then sent him to the DOS window.

I for the life of me cannot figure out what has gone wrong with it, any help would be appreciated;

Thanks

 

[bignastyid]

http://www.tomshardware.com/forum/id-2317968/read-passwords-lock-codes-pin-numbers.html