Hi,
It seems to be a crash issue. Please have the user try if he's able to edit the files when the applications start in Safe Mode:
http://office.microsoft.com/en-in/excel-help/work-with-office-safe-modes-HP010354300.aspx#_Toc312758060
Just press and hold the CTRL key, and then click the name of the Microsoft Office program that you want to run.
If there's no issue in Safe Mode, it's probably related to 3rd-party add-ins, disable the suspicious ones to verify that.
You can also go to Event Viewer to find some information that may indicate the cause:
Press Win + R, type "eventvwr" in the blank box, press Enter.
Finding useful crash data and Windows Error Reporting:
http://blogs.technet.com/b/arykhus/archive/2008/12/11/finding-useful-crash-data-and-windows-error-reporting-wer.aspx
Regards,
Melon Chen
TechNet Community Support
