Look a the screen real close, if you see a faint dark version of the image, this could be a backlight issue, otherwise a screen cable or a logic board issue. Backlight repairs are somewhat difficult. As much as I would like to be able to tell you a quickfix that will solve backlight the problem, it's a pretty arduous repair that requires 1-2 hours for a trained person. It's feasible to do it yourself if you're tech savy, but you'll most likely have to google for guides that show you exactly how to replace the backlight step by step. Check on how to take the screen apart and make sure inverter is still connected properly. If the inverter is connected and you still don't have light, then you have a backlight issue. I work for Computer Repair NYC
and i have to fix this problem a lot, it's so easy to break the lightbulb in the process.