BOAC,
I believe you may be 'overstepping the mark'. I could, of course, be wrong.
Try this: Once your data input is complete, click on Print Preview. Do you get 1 page, or 2 pages to preview? If 2 pages, is the result of the second page a line of any sort?
Without seeing your page, I am guessing that your data has slipped across your page size, so what looks like a brilliant piece of information on 1 page, has actually made itself into 2 pages. File/View/Page Break will give you a massive visual clue as to how you have made an utter mess of your SS. (JOKE!)
To fix it, (yes, we can) make your margins smaller than the default size (which are huge), so try 1.5 cm all round.
The other trick is to place your mouse cursor over the column heading line, and double click so that the information in the cell is forced to fit to how big it is. Does that make sense? If not call back, and I will do a screen grab.