My LCD T.V. is slow to get a picture?

My 16 month old Samsung LA26R71BDX LCD, is taking 15 minutes to get a picture; audio at once. Began with 4.3 vertical striping, now alternates with full width horizontal stripes, and since that problem arose, has switched on automatically on two occasions. Would like to have some ammo. to use when I start fighting for warranty etc. if no solution by me. Thank you all helpful people out there.