Hi Ambuj

You can use the below 2 scripts to check wether ur SQL server is running or not

-- This Gives u the state of SQL server, Running or Stopped

master.dbo.xp_servicecontrol 'QueryState', 'MSSQLServer'

-- You can start or stop SQL server with the line below from DOS Prompt

Net Start MSSQLServer

Remember to Start SQL Server Agent once you have started

Hope this helps