Unabe to start SQLServerAgent

Hi

I got the below error when I try to start SQLServerAgent

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Unable to start service SQLSERVERAGENT on server(####) (mscorlib)

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Program Location:

Server stack trace:
   at Microsoft.SqlServer.Management.UI.VSIntegration.ObjectExplorer.Service.Start()
   at System.Runtime.Remoting.Messaging.StackBuilderSink._PrivateProcessMessage(IntPtr md, Object[] args, Object server, Object[]& outArgs)
   at System.Runtime.Remoting.Messaging.StackBuilderSink.AsyncProcessMessage(IMessage msg, IMessageSink replySink)

Exception rethrown at [0]:
   at System.Runtime.Remoting.Proxies.RealProxy.EndInvokeHelper(Message reqMsg, Boolean bProxyCase)
   at System.Runtime.Remoting.Proxies.RemotingProxy.Invoke(Object NotUsed, MessageData& msgData)
   at Microsoft.SqlServer.Management.UI.VSIntegration.ObjectExplorer.ServiceActionHandler.EndInvoke(IAsyncResult result)
   at Microsoft.SqlServer.Management.UI.VSIntegration.ObjectExplorer.ServiceControlProgress.ActionCompletedHandler(IAsyncResult result)

Any one know how to resolve this ?

Thanks

Priya