Nef's keyboard is suddenly typing strange letter and numbers. Leo says to be sure that the numlock or capslock isn't enabled. Keyboards can also get dirty and that could cause it. Keyboards are dirt cheap, and he can buy one and make sure it's just the keyboard that's wearing out. He can plug it in a different one, and if it works, he'll know his keyboard is going bad.
Before he tosses the keyboard out though, he can actually try running it through the dishwasher to clean it. Understand though, that there's a risk that he'd break it, but a lot of times it works great. He should also make sure not to use the keyboard again until it's completely dry.