Is there any way to have a popup window appear when the user presses F3 (or
some other F key)? I am trying to create some help capability for my users.

Comments are useful but they interfere with the Validation windows for the
same cell.

I have written Winhelp files for Access but now I neex to know the best way
to create "custom help" for an Excel workbook.

Any general guidance would be appreciated.

Bill