Guess you'd need to Hook the keyboard, or maybe as you are only looking for
one particular key, look into RegisterHotKey. It would make a difference to
the complexity if you need to trap a system-wide keypress or merely in a
given window, say a workbook window.
Plenty of examples around for VB6 but I'm don't know how safe, if at all,
they'd be in VBA.
Regards,
Peter T