Keyboard keys swapped around

Hey,

The a, q, w and z keys on my keyboard have all swapped around (not physically, but when I press 'q' an 'a' is typed etc), none of the numbers and punctuation keys are in the right places either and I have no idea why.

Does anyone know how to fix this (sorry, I can't find where question mark has gone)

I'm running an Intel imac with OS X version 10.5.6

Thanks,
Tom

 

Thanks so much, I can type a message in less than a day now ! It's odd, I don't remember going into that panel and changing my keyboard settings ever before.