My Magic Mouse is not moving the pointer on the screen but it allows me to scroll up and down by sliding my fingers on the mouse.

Have you tried this:

http://support.apple.com/kb/TS3048?viewlocale=en_US&locale=en_US#7

Mouse does not track as expected (jittery, jumpy, slow, fast).

The Apple Wireless Mouse can be used on most smooth surfaces, however if tracking issues occur try these options:

• Choose System Preferences from the Apple () menu, then choose Mouse from the View menu. Set the Tracking slider to adjust how fast the pointer moves as you move the mouse.
• Try using a different surface to see if the tracking improves.
• Turn the mouse over and inspect the sensor window. Use compressed air to gently clean the sensor window if dust or debris is present.
• If multiple Bluetooth wireless devices are in use nearby, try turning them off one at a time to see if the issue improves. Bandwidth intensive devices could affect tracking.

Try a PRAM reset.

Barry

If you followed the instructions (four keys at once, etc), that should have done it. I have not reset the PRAM in a long while, so I cannot recall what happened at the time.

Barry