Here is an example that should work for you,
when trying to exit the workbook or saving it, it will automatically save Sheet 1 and not alter the original,
Remember if you want to change the original workbook, when opening the workbook do not enable macros as you will not be able to save the changes if the macros are enabled
http://www.freewebs.com/davesexcel/SaveMacro.xls

You may require additional code to ensure that macros are enabled when opening the workbook