Trying to open xlsx and pptx or ppt files I am getting an error "The action is only valid for products that are currently installed." So I can't double-click on these files. I tried opening from the file after the program is started. For Excel i get a green box for a long time and then finally the error "The file is corrupt and cannot be opened." I opened this very file last Tuesday on another computer in Office 2010; no problem. The pptx files say "The application was unable to start correctly ()xc0000022). Click OK to close the application. When opening ppt I get the valid products error. I CAN open them from inside Power Point but not double-click. I have gone to Control Panel and Default Programs and even set files for default programs. All to no avail. Help, please.