Keyboard problem


Hi, I have a Titanium powerbook G4 running Tiger and have an intermittent problem with the keyboard that is getting worse.

When I hit spacebar it types 6yhn on the screen , then when i try to delete it, i get 1qaz

i have seen other questions about this on other forums but no answers!
is it to do with the location of those particular keys?

please help as it is driving me mad! :mad:

should also say that hitting those keys darkens the screen and launches expose