Since this is your first post, welcome to the forum.
You said "can't solve it anymore." Was that a turn of phrase or did this happen before and you fixed it?
When you say "types randomly" it would help to have a verbal description of the symptoms.
Basically, if a keyboard is throwing random letters or letters with apparently random timing, it would APPEAR to be a faulty keyboard. What kind of connection do you have? The old RS232-C or a USB connection? We had one case many years ago in which we had the "Root Beer" syndrome - when a person spilled a drink into the keyboard. Even though it was originally sealed, wear had taken its tool and root beer did the rest.
So... give us more definite symptoms, please.