Give this a try. I only have later versions of Origin, but this should work with Origin 8 as well.
1) Navigate to the folder containing the workbooks of interest.
2) Open the Script Window from the Window main menu.
3) Copy and paste the below code into the Script Window.
4) Highlight the code and press the Return key to run the script.
doc -ef LB // Loop through all individual sheets in all books in the current Project Explorer folder
{
if (exist(%H, 2) == 0) // This filters our Matrix sheets that may be in folder.
continue; // If the current item in the loop is NOT a worksheet,
// then continue with the sheet in the folder.
// Now multiply column 4 by -1
col(4) = col(4)*(-1);
}
For more information about looping through items using LabTalk,
see http://www.originlab.com/doc/LabTalk/guide/Looping-Over-objs
