Two rows merged on every print out
 

I have an Excel 2003 installation that when a spreadsheet is printed, the
same two rows (11 & 12) always appear merged on the printout - the gridline
is missing between the two rows. This happens on every spreadsheet that is
printed, even a blank new worksheet. Print preview shows the gridline
present/looks normal. I initially thought the startup template, but nothing
is present in the XLStart folder, so Excel is not starting using a template.
Any suggestions or ideas would be greatly appreciated.