Does anyone know how to insert partial gridlines in EXCEL.

I have a part on the sheet that has a few rows of numbers so I want to insert gridlines in just that area.

Select the section you want gridlines on. Right click, select "format cells", then "borders". Select the line style you like, then click both inside and outside.

Instead of using the gridlines feature you could format the cells for that block to have borders. That way, when you print the sheet only those cells or block of cells with borders will show lines.