Delete Or Clear A Row If Cell In Column Is Blank

Is there a way to delete or clear a row on exit if no end date has gone into it. i.e. if the user clicks on the X button in the top right hand corner.

Every time the user clicks on start the date goes into the next empty row, if finish is clicked then the end date will go into the cell next to it. See example below. Here the user has started and ended correctly

column
AB
StartEnd
24/10/09 24/10/09
24/10/09 24/10/09

In the example below the user has forgotten to click on the finish button when they first clicked on start, they exited excel instead and no end date was inputted. When the user clicked on start again the start date went to the row below, however as there was no end date the last time, this time when they clicked on end button, then end date went to the first BLANK CELL

column
AB
StartEnd
24/10/09 24/10/09
24/10/09

I would want the delete row or clear row option, which ever would work best, to happen if the user clicked on the X in top right and corner or Exited excel via File.

Ideally I would like the row cleared and not deleted, I have read Clare Watts thread and we both seems to be having a similar problem, I have used some of the examples from her thread but non seem to work. So I now wish to go with a delete or clear row option on exit, if possible.

The row changes every time. The column for deleting or clearing would be A to AB. The end date goes in to Column B

So if the user clicked on start but did not click on the Finish Button then the last row with no end date would be deleted or cleared on exit from column A to AB

column
AB
StartEnd
24/10/09 24/10/09
24/10/09(This is deleted or Cleared of exit via X top right hand corner)