When you are unable to log into your SQL Server, one recommended solution is to see if the required services are running. To do so, you can go to Start > Microsoft SQL Server 2005/2008 > Configuration Tools > SQL Server Configuration Manager.
Select the ‘SQL Server Services’ node and you can see the services that are running. If you observe in the screenshot shown below, the SQL Server service (MSSQLSERVER) is not running
When you right click and attempt to start the service, you may encounter an error that says “The request failed or the service did not respond in a timely fashion. Consult the event log or other applicable error logs for details”
One of the solutions to resolve this error is to see if the default port of SQL Server i.e: 1433 is not being used by a different service. Click on the ‘Protocols for MSSQLServer’ node
On investigating, I found that the VIA protocol was using up port 1433.
I disabled the protocol by right clicking on it and the problem got solved