Cannot set worksheet visibility in VBA

In VBA, 'ThisWorkbook' contains code that should open a Welcome page with instructions for enabling macros if the user does not have macros enabled. Once enabled, the worksheet titled 'Calculator' should display. It was working as desired until I added the worksheet titled 'KB'.

I tried to go to properties in VBA for 'KB' and set Visible to xlSheetHidden and get an error message that Excel cannot set the visibility.

Thinking the 'ThisWorkbook' code was forcing it to display, I tried to add code to hide 'KB'. Nothing worked. I believe I undid all my changes but now when I open the workbook, the Welcome worksheet flashes, immediately disappears and the active worksheet is 'KB'.

Any ideas on how to restore the original function and successfully hide 'KB'? Note: the coding is not very elegant, I'm sure. I just started trying to learn VBA 4 days ago.