Click the mouse to position the cursor where you want to type. Either type
here, or use the backspace key to delete to the left, or the delete key to
delete to the right. If when you type other characters are deleted check the
bottom of the screen in the grey area to see if OVR is switched on. This is
the overtype. Double-click it to switch off (or press the 0 on the number
keypad). Does this help?