Removing Instances and SQL Server Express edition and going to Standard/Developer/Enterprise
(Local) without an instance name is the instance named MSSQLSERVER (the "SQL Server (MSSQLSERVER)" service).

If your only goal here is to get SSMS and SQL Profiler from the normal edition and not the express edition of SSMS that's easy, just install the tools from the Developer edition DVD / ISO.

Launch the installer, get through to the list of services.  Select only the management studio options (there are two, one under the other) and finish the wizard.  This will give you the tools and leave your instances alone.