Hello Philosophaie,
No, you can not do either. You can create the illusion of the UserForm being a stand alone by using a few tricks.
You would need to hide all the worksheets, the menu bar and command bars, and modify the UserForm to look like a window with minimize and restore buttons and save the workbook. When this workbook is launched, the UserForm is displayed when the workbook opens but application is not visible making the UserForm appear to be a stand alone application.