The Wireless Controller has a small reset button located on the back near the [L2] button. The controller can be reset to default settings quite easily by clicking this button using a small, unfolded paper-clip or something similar (the button is inside a small hole). After resetting the Wireless Controller, re-pair the controller with the PlayStation 3 system by connecting the USB cable to the controller and the system and pressing the PS button.
To check what version of the System Software is installed on your PlayStation 3:
If, after trying all of the suggestions/steps above, you still have issues with the Wireless Controller, we recommend using the restore default settings option from within the PlayStation 3 Settings option.