Change language keyboards on a laptop?

I have a chance to buy a second-hand 9400 from a German guy, who has a German keyboard on it. He thinks I can just change it to a QWERTY-keyboard, but is this really possible? It's not just a matter of buying a new keyboard; in addition to that I have to convince the computer insides somehow (which will be running a German version of Windows) that I have a Qwerty keyboard. Is this possible? Either in theory, or even better, has anybody ever done it? (Since it's second-hand, I don't think the Dell people are going to help me out here.)

--LaDonna