MBP Keyboard Problem. Frozen Keys?

My "delete" "spacebar" and "tab" keys suddenly stopped working altogether. All the other keys seem to work fine but those, no matter what I try, will not function. I've even gone as far as to reboot the system thinking it could have been a virus...to no avail.

The keys being so far away from each other makes it seem weird that just those would give out. Any help, or should I just send it back to Apple for a new keyboard?

I'm currently running Tiger OSX. I've seen problems for Leopard and fixes for them, but my problem seems different and..well, I don't run Leopard.
Thanks for any feedback.

Test the machine first before deciding on taking it in to Apple or sending to them for repair. A good test would be to attach an external keyboard to the machine. It doesn't have to be an Apple keyboard, just one that has a USB connector. Don't test with wireless.

Regards.