worst problem: repeated commands!

Hi everyone! I have a macbook pro, the old edition, 1,6 year old.
I have the worst problem ever: sometimes when i type a command, or just push any keyboard buttons my mac repeats it untill i type a new command... it's so frustrating, especially when working! if i type (cmd+z) it can erase hours of work...
I really hope anyone knows something, eventhough i doubt it! can't find any articles about it either!

on top of that my keyboard freezes once a day so i have to restart the mac...

my guarantee is out and i don't have apple care...

thanks for any kind of replies!