PC upgrade- now problem with keyboard? do I need gaming keyboard?

Hi, I recently bought and put together this from OcUK:

Intel E8400
Asus P5Q
4GB Corsair PC2 6400
ATI Radeon HD 4850

My problem is my Microsoft Comfort Curve 2000 keyboard locks up certain keys when playing games, but the strange thing is... this never happend on my old Asus 955X series mobo.

For example: Im holding down 'w' and 'shift' and if I was to tap 'alt' whilst holding down these two keys movement stops all together and no keys function untill I have let go of them all, after which I can press them again. Its very frustrating!

I have installed the latest chipset drivers, Intellipoint software etc and still same problem... like I said, strange thing is it never happend on old mobo.

So the main question is... what can I do about it? Do I need a new 'gaming' keyboard?