This procedure was posted by George Fisher in this thread, and may help you. You may also have to try "enter" and button 3.
[Link: remotecentral.com]Guy, for your reference and for anyone else with this
problem.
Sony have been very helpful. Turn on the DVD and your
TV. Press "enter" and button 1 for 5 seconds and it will
take you into Set Up. It did! Hurrah! If pressing "enter"
and 1 does not work, try "enter and 2.
I'm back in business. Thanks for your help.
George