You liking applied formatting to a group of rows or columns which would have
formatted every row or column for that particular column or row. I know
thats a lot of verbiage to sort through but stick with me. Try highlighting
all of the empty cells to the right of your data, right click and click
"Delete". If prompted chose "Shift Cells Left". Then do the same thing for
the rows below your data, but this time chose "Shift Cells Up", if prompted
of course. The reason the 2007 files (.xlsx)would be so much larger than
2003 files (.xls) is because 2007 has over one million rows worth of cells
available is every sheet and 2003 offers just over 65K (2007 is actually
limitless but the 1 million and change figure comes with every sheet you
open, hold CTL + Down Arrow til you get to the bottom and you'll see what I'm
talking about). A similar relationship exists for columns between '03 and
'07. So after you have deleted the blank, but formatted, empty rows and
columns your file size should drastically decrease.

"PeteeWJ" wrote:

An Excel file that we use is only about 2MB in size, but as soon as it is
opened, the memory usage of EXCEL.EXE jumps to over 1GB. We are running
Excel 2007 and this file is saved in the .xlsx format. Weird enough as using
that much memory is, when I save-as that file into Excel 2003 format, close
down Excel and open the new .xls file, EXCEL.EXE memory usage is only about
100MB. Why would a file saved in .xlsx format use 10 times more memory as a
file saved in .xls format? Both files are being opened through Excel 2007.