Q: Strange cursor problem

General purpose Mac troubleshooting guide:

Isolating issues in Mac OS X

Creating a temporary user to isolate user-specific problems:

Isolating an issue by using another user account

Identifying resource hogs and other tips:

Using Activity Monitor to read System Memory and determine how much RAM is being used

Starting the computer in "safe mode":

Mac OS X: What is Safe Boot, Safe Mode?

To identify potential hardware problems:

Apple Hardware Test

General Mac maintenance:

Direct you to the proper forum for MacBook :

MacBook Series Forums 

https://discussions.apple.com/community/notebooks?view=discussions

http://www.apple.com/support/macbookpro

Mac OS X Forum

https://discussions.apple.com/community/mac_os?view=discussions

This forum deals with a desktop/tower 65lb Mac Pro

http://www.apple.com/support/macpro

TimeMachine 101

https://support.apple.com/kb/HT1427

Mac OS X & Mountain Lion Community

https://discussions.apple.com/community/mac_os

https://discussions.apple.com/community/mac_os/os_x_mountain_lion?view=discussio ns

Recovery Mode

http://support.apple.com/kb/HT4718

Unless you did a clean install, and I can't tell what your system maintenance is whether it is what I would do. Backup / clone your system, use ML RECOVERY and erase the system partition and update with just Apple updates, don't restore anything.

Run Apple Hardware Test.

Take it in for a free check and diagnosis.