Unfortunately, I had to learn how to do this today. 🙁 I spilled not one but two cups of water off my nightstand onto my Dell laptop (don’t ask how). Somehow, the core of the laptop didn’t die, and I guess the keyboard didn’t literally die, but any keypress generates 15 random key strokes. *sigh* Mebbe eventually the contacts will finish drying out and it’ll start working.
Mebbe…
Source: Is there a way to disable a laptop’s internal keyboard? – Ask Ubuntu