I need help with line 3 of the following:

[1] Spreadsheet1 is already in use
[2] User opens Spreadsheet2 (from desktop shortcut - bypassing Excel menus)
[3] Code in the Spreadsheet2 Auto_Open() macro detects that Spreadsheet1 is
already open and in use
[4] A warning message is displayed
[5] Spreadsheet2 automatically closes

Regards
McBarker