123 keys not working on extended keyboard usb

Hey everyone

My extended keyboard isn't working properly. 0.Enter123 are not functioning. It doesn't appear to be a number lock issue as the rest of the number pad is functioning. I'm thinking its software related. Anyone experienced this problem?

Set up...

iMac (21.5-inch, Late 2012)

2.9 GHz Intel Core i5

16 GB 1600 MHz DDR3

Yosomite 10.10.2

Cheers