problem fixing lexsor lcd tv?

I'm a bit of a newbie so be gentle...,
I have a lexsor lcd tv, put it in repair shop but they reckon it can't be fixed, - i dunno if they're just trying to sell me one of theirs - of if it really can't be fixed.
The problem is: - i have multi coloured streaks on my screen, anyone got any ideas on how to fix it and what i would need,

thanks in advance