Q: My mouse pad is continuously going 'crazy'! It won't move and when it does, it doesn't go in the intended direction. How can I fix this?

Reset SMC.     http://support.apple.com/kb/HT3964

Choose the method for:

"Resetting SMC on portables with a battery you should not remove on your own".

Jumpy Trackpad

http://support.apple.com/kb/TS1449

                    
If this problem  continues, you may have to take the computer to the Apple store to have it checked out.

Best.

resetting the SMC worked for my wonky trackpad! Thank you!

Thanks dominic23 for the solution...this worked great for me.  I was worried I'd have to replace my trackpad or just lose it and go with a wireless mouse ($$).