If you need to "start from scratch", it can be useful to completely disable all replications within a SQL Server instance.
For more information on the Microsoft SQL Server Management Studio, see your SQL Server documentation.
Open Microsoft SQL Server Management Studio. In the Object Explorer, expand the server instance name you want to disable.
Right-click Replication, and select Disable Publishing and Distributor.
Follow the instructions in the SQL Server wizard.
If a database uses two-way replication, as with the Model database, you still have to remove the replication coming from the other servers before you can delete the database.