Excel 2007 Hiding/Unhiding Worksheets Using Code

Hi All,

Trying to automate time sheet process by having staff enter data in Excel. I have a workbook with 40 worksheets. First worksheet is called "menu" and the others are named by staff. I want the workbook to always open with worksheet "menu" displaying and the other worksheets hidden. Person would select their worksheet name on menu worksheet activating that worksheet. Can someone help me with:

On opening workbook how do I only display worksheet "menu" and hide the others.
When person selects worksheet name from menu worksheet how do I only show that worksheet - if they change the worksheet name I only want the last one they chose to display.

Thanks much for any help.
MB