Inverter or Backlight?

Okay, so here's the thing....  when I turn my laptop on ,the screen is really dark. It almost looks black. The only way I can see it is if I either put it in the sunlight to use it. Or put a small desklamp upon my laptop and have the light directly shining on it. My question is, is this a backlight issue, or inverter Issue? I have a DELL inspiron 8600 and they told me I would have to replace the whole screen which is going  to be $400 for the screen alone. I do not have that kind of money. Ebay does sell the same screen for less. They also sell backlights and inverters. What do you think I should do? You can tell with light on the screen that it does have its color and all, its just missing the floresent light behind it to light up the screen. I was going to just buy a new laptop, i've had this one for about 5 years. I just dont have the money right now to do that. So if there's a better solution i'd rather not have to buy a new laptop.