Keyboard Charachers mixed up

Hi,
I am having a problem with my keyboard registering double letters when I tap the keys once. I am not sure if it is hardware or software related. Most charachters are fine but when I type the letter "g", I see "g5". Letter "h" becomes "h6". When I type the numbers 5 and 6 I also get "g5" and "h6". A few other punctuation keys are also registering double charachters.

So wh6en I type normally, it looks like th6is. I h6ave looked online and found a few oth6er people h6ave h6ad th6e same problem on several different systems but none of th6e proposed solutions h6ave worked for my laptop.

When I use the onscreen keyboard, it works normally.

Here is what I have tried:

doing a cold boot
fiddling with the Fn and Num Lock keys
fiddling with the filter keys and sticky keys settings in Vista
replacing the keyboard
uninstalling and reinstalling the keyboard drivers (standard ps/2)
Since my computer is still under warranty, a technician came out and replaced the motherboard (and the keyboard a second time)

None of these solutions have solved the problem!

Please help.