There should be a number of Posts about removing the /20042005/2006/22007/2008 era bulbous TVs. There is usually a screw from the right side into the TV. It is hidden under a wooden plug in the frame. Additionally there are likely screws going up from the cabinet under the TV (if you have a fireplace, you might have to remove it).
I know BB_TX posted a bunch about his conversion to flat screen TVs.
Here is one but unfortunately the pictures are gone.
https://www.montanaowners.com/forums...ad.php?t=49087
Here is another:
https://www.montanaowners.com/forums...ms=flat,screen
Do a Search on "flat screen" and see what you can find.