First off .... How long have you had him/her? How big is he/she? Whats the enclosure like, temps, hides, humidity? Are you trying to feed live, pre killed, or frozen/thawed? If you are feeding rats, have you tried mice and vice versa? Have you changed anything in your set up recently? How badly can you see his spine ( do you have any pics )? Does he have any other noticable injuries? Have you thought about going to the vet?

I would definitely resort to force feeding as a last resort. I had a bp go for at least 4 months without eating ( thats as long as i had him before he ate, dont know anything about him before i got him ) and am just now starting to get him back to a good weight. Two weeks isnt an incredible amount of time for a bp to go off of feed, and i've never heard of one starving itself to death ( not to say that this couldnt happen, i've just never heard of it ).

If you could provide a little more information we might be able to diagnose a potential problem better.