There may be times when you receive a workbook from another individual to work on.  It is possible that a portion of the grid lines on the worksheet (or all of the gridlines) may not be
visible.  There are a couple possibilities as to why the gridlines are not visible.  Gridlines can easily be turned on and off with using a setting in Excel 2007 & 2010.  There are additional videos available for working with other versions of Microsoft Excel.