Pelikal, you MUST use the number pad to input Alt-code unicode characters. Normal number row below F-keys won't work. There's probably an Fn (function) key plus one of the F-keys to get num lock to turn on.
Then, you'll be able to use the number pad, which is probably indicated by small blue numbers underneath the letters to the right side of the keyboard.
Or, just boot into Safe Mode, login with the included administrator account, and reset your password
