When Turned on the Screen says ''Locked''

It is locked. Unlock it. If you wish to get some details; check the site linked here. Pull up older posts.
http://electronicshelponline.blogspot.com/
Unlock procedure and to override the password lock to many popular brand TVs are given. Search the site by type in this key phrase "How to unlock television"; in the search box at the top left of the display window, to get gathered related posts.

That's a fairly old TV...The locked means that specific circuitry is locked because if running it would cause a major problem, and that is also why it shuts off. You are going to have to find someone familiar with Phillips TV's.

Hello
You must have its original remote control handset to unlock your Mitsubishi tv.

After you set the lock, you must use your pass code

to view a locked program, view the locked TV, view

a locked channel, cancel the lock, or enter the Lock

menus.

If you forget your pass code, you can view the locked

TV without entering your pass code. When you are

prompted for your pass code, press the number 9 and

QV keys on the TV remote control at the same time. This

process temporarily unlocks the TV.

When entering the Lock menu, this process deletes

your old pass code and prompts you to enter a new

pass code.

• You can either enter a new pass code to open the

Lock menu and make changes or press EXIT to close

the menu.

• If any of the locks are turned on and you exit the

menus when prompted for a new code, the old

code and all lock settings are retained.

• If all locks are turned off and you exit the menus

when prompted for a new code, then the previous
code is erased.
OK.

got to manufacturer website find your model tv download manual from there

Try this: press "Function" and "Mute" on the remote at the same time. This will unlock the channel. Do this if you want to bypass the lock to watch a certain show or channel while leaving the TV locked. All other channels will remain locked and the TV will lock again when it is turned off.
Unlock all of the channels on the TV by entering 0711 or 3308. These are the Jensen factory reset codes that will reset the TV to the original factory settings. By doing this, you will loose any information that you have stored in the TV, such as channel labels and schedules. You will have to program the TV again by going through the entire initial set up.

Try resetting the TV to factory settings thusly:

Turn on the TV. While holding down the RESET button on the remote
control, press the POWER button on the TV. (The TV will turn itself off, then
back on again.) Release the RESET button.

Owner's manual available here:
http://www.docs.sony.com/reflib/docget.asp?manualid=9635&template_id=1&region_id=1&DL=

Just like a few of your other readers mentioned, we pushed the button below the AV/TV button for 3 seconds and the screen unlocked. Thanks for everyone's advise, we were ready to throw out the TV.

if its 1 month old call for service your under warranty

First you need to get your remote working, without it you cannot unlock the tv. If the romote is not phisically broken (or smashed) make sure the battery contacts are clean and install new batteries.
Once you get the remote working (hopefully) Enter the MENU and select 'Features'. Set the Child Lock to OFF. If you cannot get the remote to work try a universal remote, setting it up with the codes for your tv provided in the setup manual for the universal remote.

To turn off "Control lock" : press and hold the "End of cycle signal" button for three seconds.