Unhappy [Q] unable to mount system

I was running the latest CleanRom on my nexus 7 tablet and it randomly rebooted and stopped working. The tablet now doesn't want to boot into the OS. When i boot into TWRP recovery mode i need to wait at least 20 minutes before the TEAMWIN splash screen goes away and finally boots into the TWRP recovery interface. I'm trying to reflash a rom but it fails everytime, in doing so i'm prompted with a log message that says "/system, /cache" was unable to mount.

My biggest concern right now is getting all my user data such as music, document, books, movies off of my tablet so i can restore the tablet to factory defualt. Is there a way to recover such files? (~26GB of Data)

This is what i have tried with no luck:
  • TWRP backup of user data to OTG USB
  • adb install of factory image. (-w removed from bat file)
  • Nexus root toolkit 1.7.9 backup of virtual SD. (says successful but backup size is 0MB)