I dont know what to suggest to be honest, you've either got the drive to succed and reach your goals or you dont.
I used to be the same, ate rubbish, played computers games all day etc, till i decided to get off my arse and stop being a bum. Got myself down the gym, got myself a diet and routine sorted and have been doing it for months without fail now. Bearing in mind i never had any weight to lose, i did this purely to gain muscle mass, but im so happy i did it.
Keeping fit is a lifestyle, if your going to do it, its going to take alot of time and dedication to succed, but in the long run it'll be worth it!
d00d