Keyboard stopped working for one user - and one user only

Since yesterday, my keyboard stopped working. I type but nothing appears in the text неудар в лунку. If, for example, I press "Enter" on the browser's address бар, не request will be made. The мышь works perfectly, but both my notebook's keyboard and the USB keyboard I использовал fail to work.

It only happens with my default user account: if I log into another account on my machine (Ubuntu 14.04 with Unity) it will work; it also works at ttys. However, if I lock my default account, the keyboard does not work at Light DM either.