I decided to open up the tablet because I figured it was a loose cable, but I can't figure out which cable connects to the display. I'd appreciate it if anyone could help. Here's the pics of the cables http://imgur.com/a/hettF.

Someone else with the same problem

I have had the exact same problem ever since I bought the HP Spectre. It is definitely a hardware problem. My screen originally did the flickering thing, and then eventually the screen would just not turn on. Everything else would work, except the screen just stayed black. I called HP and went through hours and hours of diagnostics with them, to no avail. So, I opened the computer up and figured out that the genius people who designed the computer made the wire that connects the screen to the motherboard too long, which caused the wire to either be very loose or not connected at all. I connected it back securely and taped it down and my problem went away. However, my screen still flickers when the tape comes loose and I have to open it up and fix it again. If you have a better solution than tape, please let me know because this problem is getting on my last nerve