Touch Screen not reacting or acting on its own
Please calibrate the Touch Screen. Choose the option 'Touch Screen' in the Nintendo DS Lite options menu.
Please make sure you exactly tap the displayed calibration points (upper left corner, lower right corner, middle). If you have done this correctly a message 'Calibration complete' will show up.
If you use a protective film on your Touch Screen please be aware that this can reduce the sensitivity of the Touch Screen. In addition, if the protective film is not attached properly, the Touch Screen can receive wrong control impulses, which can influence your ability to control.
In this case please remove the protective film and re-calibrate the Nintendo DS Lite as described above.