If you suspect that the touch screen is not functioning properly, go to the Windows desktop and move your finger across the screen. If the mouse pointer moves directly under the tip of your finger, touch functionality is working correctly. If the mouse pointer moves more than half an inch (1.3 centimeters) away from the tip of your finger, start by cleaning the screen. To do so, with the computer off, moisten a soft, damp cloth with water and gently wipe the screen to remove dirt and smudges.
If touch functionality still is not working correctly, calibrate the screen.
In the Windows Start screen, type Tablet PC Settings to open the Search charm, and then select Tablet PC Settings from the results list.
Figure : Search results for Tablet PC Settings
Tablet PC Settings window opens. On the Display tab, click Calibrate.
Figure : Calibrate selection in the Tablet PC Settings window
Follow the on-screen directions to calibrate your screen.
Click Yes when prompted to save calibration data.
If the screen is still not calibrated correctly, undo the calibration by clicking Reset on Tablet PC Settings.
Figure : Reset selection in the Tablet PC Settings window
When prompted, click Yes to allow the Microsoft Digitizer Calibration Tool to make changes to your computer.
The Digitizer Calibration Tool window opens to confirm that the calibration data was successfully removed.