hmmm, this issue seems to be an excel problem, not a SAS problem. It also sounds like you're doing it correctly in Excel to turn off the 'always create backup'. Is it an option to reinstall Excel?
From stackoverflow.com:
What you need to do is open any excel file and choose the "save as" option. When you are in the save as window, below the "File name" and "Save As Type" options, there is an option that reads "Tools" with a small drop down arrow next to it. Click on this drop down arrow and then from the dropdown list, choose "General Options". In the window that pops up next, check the box that reads " Always create Backup"
