SQL SERVER 2008 R2 SP2 APPLYING AFTER GEETING ERROR

HI,

I had updated 2008 R2 (RTM) VERSION to sp2.After that I was unable to open the SQL server instance and getting error messege

Like "Error: 18401
Login failed for user '<abc><login name><abc>'. Reason: Server is in script upgrade mode. Only administrator can connect at this time."

note : here i am the Administrator.