Nexus 7 wont appear on my PC in the bootloader, semi bricked So I tried to root my nexus 7. I realized I done screwed up. However, when I looked for my SuperSU installed file in TWRP, I forgot to install it before hand, when I was at my bootloader, or before that. Now my Nexus 7 will not appear on my P.C to save my life. I have tried it one 2 different cables and PCs. It won't appear as a media device no matter what I try. I also cant open up the OS for some reason. I followed this guide and that did solve my issue of having TWRP. Say I have 0mb internal storage, but I still cant install super SU, or boot up my OS. Whenever I try and start it now I get a slightly lit black screen forever. 

EDIT: despite all this I am able to do commands like flashing 
EDIT JUST A FEW MINUTES LATER: removing TWRP via fastboot erase or something, then reinstalling allowed me to see my nexus on my computer, install super SU, and reboot... into a still black screen. i guess ill try and reinstall the system os rom?
EDIT: A few hours ago I reinstalled and flashed the System.img Straight from motorolas website. It worked. Thanks if you helped.

TL/DR:
Device won't show up on my PC. Device is semi bricked in bootloader.
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