Maplin/RS or any other electronics components shop will do.
It'll be a momentary switch you need, but the fun bit is finding one the right size and shape to replace your broken one.
Failing that, try emailing Medion. I've found that a lot of manufacturers are pretty decent in supplying replacement parts.
You could also buy a whole new replacement case. That's a hell of a lot more expensive than a switch (20+ pounts as opposed to 1 pound for a switch) but a new case has its advantages too, if you aren't happy with your existing case. (too big, too small, not enough expansion, ugly, etc)
Gary, November 2010
