You may want to look at

VBA Timer object for developers (beta version)
http://www.tushar-mehta.com/excel/software/vba_timer/

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Regards,

Tushar Mehta
www.tushar-mehta.com
Excel, PowerPoint, and VBA add-ins, tutorials
Custom MS Office productivity solutions

In article ,
says...
I wish to build some functionality where I can (over a network) force a
workbook to close if it has not been used / lay dormant for a period greater
that, say 10 minutes, so updates can be made from a master workbook.

I appreciate this is a bit of an odd ball, but any ideas