Cannot connect to MSSQLSERVER in Windows 7

I don’t know  if am a lazy or stupid man. MSSQL Server installation makes me frustration for few days, install and uninstall this stuff. For the first time, I install SQL Server 2008 R2 in Windows 7, for prerequisite, I install framework 4. But in the fact, SQL Server 2008 R2 needs  Microsoft .Net Framework 3.5.1, so we must install it although we have installed framework 4.

If not installed .Net Framework 3.5.1, when installation progress, an error shown for debugging. In Windows 7, you can turn on it from Control Panel\Programs\Programs and Features.

After that, the installation process will be successful. When you connect to database engine server, don’t forget to use server name/(instance name like MSSQLSERVER) -> servername/MSSQLSERVER  in server name. This thing that make me headache for a while, because all configuration setting well and service for it is running, but …