By "keyboard" assume you mean on the "on screen" soft keyboard.
The screen needs to be aligned by each user because of perception
issues... i.e. the stylus "points" to a spot beyond the actual stylus tip.
When properly aligned, each key will "flash" when tapped... if the key
does not "flash" when tapped... if the del key does not flash, you
should assume that the touch screen is defective at that location.
Beverly Howard