Weird Glitch when typing 'b' and 'n' keys

Hi guys,

I'm running Windows 7 on an HP Pavilion dv7 Notebook PC, Service Pack 1.

Basically what happens is whenever I type 'b', it comes out as 'b4', 'B' comes out as 'B$', 'n' comes out as 'n7' and 'N' comes out as 'N&'.

This was a pain to type because of this problem. Wondering if you guys have a fix. Thanks.

Note: Sometimes this will go away for a day or two, but always comes back. Literally just now as I am typing this sentence it went away, but it always comes back (lol). I was wondering if you guys have seen this and have a permanent fix. Thanks :)