dissallow characters

[Dave]

I have a form that emails a sheet and uses the input from
a cell on the sheet to name the emailed workbook. Because
of this I want the user to "not" be allowed to enter
certain characters that can't be part of a filename such
as [ ] \/ etc into that cell. Is there a way to do this?

Any help would be much appreciated.

 

[Tom Ogilvy]

use data=>Validation