I have a PowerBook G4 that's about 2 years old, and whenever it's plugged in and sometimes not, if I type a 'w' an 'e' will appear, and vice versa. It's almost as if a ghost were typing 'e' after I type certain keys in the vicinity of the 'w'. It's very strange, and annoying, sometimes I get strings of 'e's out of nowhere. 