Unlock TV. When i looking the television accidently press the remote button. And Showing the lock

Question

When i looking the television accidently press the remote button. And Showing the lock on the tv screen.Not moving the any programme.when i pressed any one botton of the remote , it showing only lock on the screen. can you help me .

My TV is a 54 cm colour receiver ECCO. When switched on the screen remains bleu with a lock displayed on the top right hand side.
I don't have the operating manual. I can't unlock the screen