Keyboard Problem

As you can see by the Subject I have lost my **key. It just turne up missing. I have tries other keyboars an have the same problem. I think I may have a OS problem.

iMac 20" early 2008
Mtn Lion 10.8.4
wire alum keyboar

Hello - I'm not completely understanding your issue w/ the keyboard (KB), i.e. I'm assuming that you mean the * key (i.e. Shift-8 on my MBP KB) is no longer working - correct? And that your tried other KBs w/ the same result - were these wired (USB) & wireless ones? Has the key been re-assigned as a shortcut? Have you checked the settings in the KB icon in 'System Preferences'? Have you rebooted the machine? Good luck and please post back your results.