Prevent saving

If you search the forums, or even google, this can be found quite easily...

In the future try to do so first, otherwise put this code in your 'ThisWorkbook' module (push alt+f11 to pull open your vba editor, double clik 'thisworkbook' and copy/paste the following code, then save the workbook - follow these steps and you will no longer be prompted to save).

Private Sub Workbook_BeforeClose(Cancel As Boolean)
ThisWorkbook.Saved = True
End Sub

You can disable the file save menu by exploring the commandbars feature...

You could do something like...

Private Sub Workbook_Open()
CommandBars("File").Controls("The Name of the control you want to disable").Enabled = False
'note, a control is simply the name of the function you want to use on a menu, such as click "File" >> Then click "Save" - in this case, the commandbar is the file menu, and the control is "Save"
End Sub

You can't prevent them saving. All they need to do is open without enabling macros.

Disabling a commandbar on opening will require it to be restored on closing.

You can 'prevent saving' using the workbook as an AddIn.

Or

Always offer the user a copy of the 'not-to-be-saved' workbook, using

Workbooks.add "E:\OF\original.xls"

If you want to assist the user maximally you'd best use a userform.