MacBookPro: bug with key $

[silexxx]

Hello,

I have a really annoying issue with my keyboard: the key $ is not working correctly:
-When I press the key, nothing happens
-The key is randomly writing symbols ($ or *) while using the computer.

I'm using Mac OS X 10.7.4 on MacBook Pro

Could you please advise ?
Is it a known software bug or should I bring the Mac back to apple for reparation ?

Thank you

 

[Dangerous Theory]

Have you ever spilled liquid on keyboard?

 

[silexxx]

no, never.
Is there a way to replace the faulty key, or to deactivate it ?