keyboard types numbers instead of letters

Hi,
I need help please,
When I turn on the numlock button and try to type, my keyboard start typing numbers instead of letters. I tried all types of solutions but no luck.
I even replaced the keyboard but still the same issue.
Please help,
I have new hp motherboard dv9225us, win7 ultimate sp1, 2 gig ram, 2 ghz.
Thank you all.
Sincerely,
Sam.