As far as I understand you, you want to start/stop SQL Server 2008 from command line.
The way you describe, using net start/stop is a crude way but it certainly works...
The following services are associated with SQL Server 2008 and you may/may not need them. The actual "server" is "MSSQLSERVER". Please note that you need an elevated command prompt to start/stop these services.
net start MSSQLSERVER -- only this service is actually "needed" to run SQL Server---
net start SQLServerBrowser
net start SQLSERVERAGENT
net start MSSQLServerOLAPService --analysis services--
net start ReportServer
To start/stop services and more administrative tasks you would usually use the SQL Server Configuration Manager you can see in the screenshot below: