I don't know why this would happen unless a macro disabled this command.
Try using View, Toolbars to display the Protection toolbar as an alternate
approach.

To reset your menus use View, Toolbars, Customize. Then on the Toolbars tab
scroll down to Worksheet Menu Bar and select it (it is already checked).
Then click Reset. If Protection was disabled by macro this will enable it.

--
Jim
wrote in message
...
When would Tools - Protection be greyed out? This isn't a shared
workbook and the workbook is unprotected, but the worksheet is
protected and I have the password. Unfortunately Tools - Protection
is not available. I'm using Excel 2003, professional edition, although
I previously saved this workbook in an earlier version of Excel.