Hi and welcome to Just Answer. I'm sorry to hear about your TV. To help me, can you tell me the make and model of the TV?
How old do you think it is?
According to your description it is one of two things...
Each of the 3 primary colors in an older “Tube” TV has it's own driver circuit. This is most likely your problem. It could be something as simple as a transistor and possibly some support components in your green driver circuit. The other possibility is the color gun in the tube itself has gone bad. If you have electronic repair knowledge then you can certainly attempt the repair it yourself. However, if you do not, it is VERY dangerous or even deadly in the back of these sets and you should call a technician for the job.
Now comes the question... Is it even worth fixing? Well, you got a lot of good years out of it. Quite often does an older TV get repaired just to break down again soon after. Picture quality and technology has come so far since then they you may want to consider investing in a new unit. The new F.C.C. Digital broadcasting rules will also affect every older TV to the point that very soon you won't even be able to receive a broadcast with out a signal conversion box. I hope this helps...Good luck.