suddenly key 'p' is doing strange things I have macbook pro early 2011 and i have upgraded the os to mountain lion.
Today key 'p' is doing strange things. 
p0p0p0
--/p0p0
-/-/p0
\p0

above things came when i am pressing 'p' key, onscreen it shows volume notification and reduces the volume. 
so now its working like F11 key and printing garbage things.

How can i trouble shoot this p key problem?
Note: in this post i have used p using copy paste.
You have spilt some (lots) water on your keyboard. Or less likely, some connectors got broken and are touching each other. Take it to your Apple Store, they will (usually) fix it for free. Or if you’re adventurous, open the thing up and let it dry for a couple of days in the shade.