TV green light comes on a few seconds and then

Sounds like the TV is in an error condition, and will not stay on (I know... duh).

The decision you need to make is whether or not the TV is worth calling an on-site TV company to diagnose and then perhaps fix the unit.

Best guess is:
$100 house call by "Atomic Television Fixers"
and $250-$400 for whatever control board is bad.

Again, how bad do you want to keep that television around...

Oh, by the way, that TV was probably delivered in one piece, but it will come apart in two major pieces for movement in tight places or removal from same. This procedure is described in the literature that was in the box when your television was delivered.

Best of luck,
Rob