Hello ubiquitas,
Sorry, but only one QuickBooks company file can be associated with one Method account. A new QuickBooks company file would need to have a new Method account. However, if you have a Multi-Tenancy account, you can sync a different QuickBooks company file to each tenant account. This option is useful for organizations with several different geographic locations.
Remember, if we were to reset your Method account, you will lose ALL your data and customization. However, if you were to start a new account, what you can do is use the Copy/Import Screen option and import your custom screens from your original account. To do this go to Customize > Screens > scroll down and click the Copy/Import Screen... button.
Hope that helps!