Some background info: I have a Lenovo Y50, I believe it's the y50-70 variant, but I'm not 100% sure. It's a 15.6inch with an i7, 16gb ram, sata drive, and an Nvidia 860m with 4gb of graphics. It was purchased in September of 2014, so it's a fairly early model of the y50. it's a bit beat up, but hasn't had any major functional issues to this point.
Now to the actual problem: When I boot the laptop, the keyboard backlight and status lights on the front all come on like normal, but the screen stays black (not just a black image being displayed, the screen is off). The problem has occured in the past, but was intermittent and could be fixed by letting it sit unplugged with the lid closed (I have no way of knowing if this actually helped, but it usually booted after that) for a few minutes before trying to boot again. The problem now seems quite permanent. I removed the backing last night and took a closer look, and the connections all appear to be fine. I'm not sure if it's relevant or not, but the laptop was left unplugged and powered off for about 72 hours before it refused to boot. The status light indicates that it still has battery, and I've tried it both with and without having the charger plugged it. I've also tried it with an external monitor without success.
My initial inclination is that there is a problem with the graphics card, or some other internals rather than the screen itself, but I really have no way of knowing, as hardware isn't my area of expertise. I'm a CS student, so if anyone could post answers ASAP, it would be VERY much appreciated."