Hi,
· Which operating system do you use?
· What do you mean by ‘never heard of it until windows 7’?
· What files are you trying to open?
· Were you able to open it before on the system?
· What is the exact error message and when do you encounter it?
· Do you remember making any changes to the system?
· Since when are you facing this issue?
It seems that Windows shell commor is a third party software, I would suggest you to contact the manufacturer of the program.
It might be that the program is corrupted, I would suggest you to uninstall it from the system and reinstall it again and check, whether the issue is resolved.
Uninstall or change a program
http://windows.microsoft.com/en-us/windows-vista/Uninstall-or-change-a-program
Thank you and Regards.
Thahaseena M
Microsoft Answers Support Engineer.
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