If you make the assumption that the screen is trashed, you have nothing to lose by trying to fix it. I would look at either the CD repair kits or the new automotive headlamp repair kits. Both will have you use a combination of abrasive polishing and a polyacrylic filler for the deep scratches to get a smooth finish back.
Personally, I'd try the headlamp kit as it provides more bang for the buck. It is designed to handle larger areas.
If it doesn't work, then you need to contact Samsung and get a replacement screen.