You could hide the worksheet at Format>Sheet>Hide.
Then Tools>Protection>Protect Workbook. Check Structure and Windows.
Supply a password.
Note: Excel internal workbook and worksheet security is quite weak with password
cracking programs aplenty for those determined to view your worksheet.
The general rule is...if you don't want users to see the data, don't include it
in your workbook.
Gord Dibben MS Excel MVP