Using subscription Office 365, on Windows 8. Lost the ability to use Excel and Outlook Exchange. There seems to be no way to fix corrupt files in Office 365. I need to have Excel on local computer so program can access it, Otherwise this program continously search for Excel, and not finding it will not open. I tried Sys Restore, but it could not restore files successfully. The program that I cannot use is Quotesoft estimating program. Can I install office 2010 to get needed Excel program? Thank you for your help.