You might have added an installer by right clicking the design view of your Windows service class. If you have done this then you will find a ProjectInstaller class within your WindowsService project.
By selecting this ProjectInstaller class you will find two installers on its design view ->
1.ServiceInstaller1
2.ServiceProcessInstaller1
Right click the ServiceInstaller1 and select properties. In the properties window change the ServiceName to the name you want to give to your service.
Hope this works…