When you turn on the TV the screen has grren lines for about 5mins then the screen has trouble trying to hold picture it takes about 2-3hours to settle what is causing this and is it worth fix it ?

Power supply Caps. Have someone replace them.

Try changing the input device to something you are sure works. If problem persists, it can be due to dry/leaky capacitors and/or dry solder on PCB. Anyhow, this might then require attention by a qualified service technician.

is there retrace line with red colour then off agian.if yes there is red gun problem which is shorted with ground.you have to do give another way heater ac voltages or replace picture tube.

if the tv width is ok try entering to service menu (do not use remote control) as follow:
1) turn the set on.
2) press the menu button and hold it down while pressing the power button.
3) while holding down the menu button release the power button and press
the volume + button.
4) The screen will display a one line menu, on the left the parameter P00,
and on the right the value of the parameter V00
5) release buttons.
6) using the volume + button change the right parameter until 76
7) using the channel down button change the left parameter until 06 (vertical size)
8) whith the volume + or volume - adjust the screen size.
9) when your tv is OK back to parameter 00 using the channel up button.
10) press menu button.
and trouble solved.

Ur convergence it dead.U know how solders?Buy a convergence kit use what in that kit.Tries Websites.Tv repair World.com,Tvrepairkits.com.

power inverter board is dead.
need a new one.

http://www.fixya.com/support/r741402-polaroid_flm_373b_lcd_tv_black_screen

With it only being about 3 years old, I would suspect bad solder connections rather than defective components like Capacitors. You may get the symptoms to come and go by slapping the side of the set or jaring it slightly which would prove the bad connection thesis. It is not a permanent cure however and you can make it worse if you keep doing that. A solder repair shouldn't run over $225 in my opinion.

replace the pcb convergence board,, It costs $96 and takes 10 minutes to replace you will have to manually line up your convergence afterward as the settings go to factory default. Everyone that owns this set has or will have to replace this part within 3 years
http://www.samsungparts.com/search/search.asp
Or Vance baldwin online
Part number bp94-00155a