When is a Z a Y and vice-versa

[peeteechase]

I picked up a Sony Vaio on Ebay and it turned out to have a German Keyboard. Not a problem except after a reload the Z and Y keys seem to have interchanged with the keyboard set to DE.
They come right again if set to English but then a lot of other keys don't tie up like :@<> etc.

Any thoughts on a solution please?

ATB,
ptc