Hi, and thanks for reading. I was hoping you could help me diagnose what's wrong with my Macbook Pro (13-inch Retina MBP, A1502, late 2013). To go straight to the symptoms, skip the next three paragraphs and go to "1 ..2...3..." etc.) I first noticed some an issue about 2 months ago where the computer wouldn't come out of sleep nicely. The screen would stay black and then randomly come back to life. Also, my audio jack has been acting up (when plugging out headphones I would sometimes not be able to change the volume), but this may be unrelated I had tried resetting the RAM by holding cmd+option+p+r and rebooting. This seemed to have solved the screen issue but not the audio-jack issue (which, again, may be unrelated). Today, things went haywire. I noticed that the computer rebooted although I didn't shut it down. Strange. A few different things have happened since. -- Symptoms: 1. Sometimes the computer would boot normally; then after a minute or two the "are you sure you want to shut down your computer now" window appears. Even if I click "Cancel" the screen will go black another ten seconds or so after that. 2. Sometimes it will boot halfway and then go black again 3. Automatic reboots ("reboot loop") Is it an issue with pram or nvram? is it a graphics card issue (i had issues with my 2011 15 inch mbp but never heard of any graphics card issues on later retina models. Things I've tried: 1. reset the NVRAM (cmd+opt+p+r). The result is a reboot loop 2. restart in Diagnostics (opt+d). The result is it says "serial number could not be found - needs service" - and then i can either restart or shut down Any ideas what I can try? Any idea what the diagnoses may be? Thanks!