Missing DVD drive

My laptop is three years old and, as it has been flown around the world a few times isn't exactly in mint condition. I have a problem with the DVD drive. It worked fine when I bought the computer, but about a year ago it started giving me problems.

Sometimes it's fine, but if I move the computer or it gets any little knock it no longer recognises the dvd drive. When I open my computer the icon isn't there and if I put a dvd in nothing happens.
This can continue for up to a few months until the icon magically reappears and it's all OK again. Apart from that the laptop is fine.

Any ideas? I think it's a physical problem. Can it be fixed or should I get an external one? If so, please advise as I know nothing about it.

Thanx

Actually you could build yourself one. Get a 5.25" in. enclosure and a DVD-RW drive from Newegg.com and put them together.