Very Strange PS/2 Keyboard Issue

Hey, I hope someone can help.

I recently replaced my Toshiba Satellite A350D Laptop keyboard with a replacement piece, made by Toshiba and as far as I know the same keyboard essentially. Is the exact same in appearance to my old one and fitted perfectly into the laptop.

HOWEVER...

When I turned on the laptop, the keyboard refused to work. It was recieving power and responding as the CAPS, NUM and SCROLL LOCK lights were lighting when pressed. The keyboard also allows some letters to be pressed and will respond but strangely the only letters it allows are vowels, and it shows them with Umlauts (a German symbol, an apostrophe above the letter) and the only number that works is 4, which has been replaced with the Euro currency symbol. I found this highly strange, as the key printed was the dollar currency symbol. Sometimes it also fails to respond to vowels at all, and the only key that works is the 'S' key, which brings up the shut down menu, it's impossible to deal with since I'm unable to log onto my computer because of it. Luckily I'm using an external keyboard for now, however my laptop is relatively immobile while I'm doing this which sort of defeats the point.

Could this be a problem with the hardware? There are instances where the keyboard works perfectly with absolutly no problems however the problem returns after the computer is shut down, restarted or put to sleep.

I've spent about 2 weeks trying to figure it out and I'm really losing work time trying to get this thing fixed so i thought I'd ask around...any ideas would be much appreciated!!

Thanks in advance.
James