Of all the weird things happening with a corrupted normal.dot this would be one of the weirdest. But one never knows.
So go into Windows Explorer, find all occurences of a file called normal.dot, delete them and see if Word now behaves.
Otherwise, I suggest using the delete-key, which in this situation behaves exactly the same as the backspace, as far as I can see.
i have microsoft office 2003 and the backspace key works but when i highlight a word and use the backspace key the word does not delete. this has only happped with Microsoft Word the backspace works every where else. does any body know how to fix this,(i tried to reinstall office and that did not work)