LG Flash tool won't recognize my LG G Pad LK430

[buzz86us]

I am trying to refresh my LG G Pad, because for some reason it boots very slowly. I had previously had it rooted in order to remove the stock rom garbage, now it is nagging me to update and it always fails because i modded the stock rom... I followed all the instructions, i tried version 2016... I got the device into download mode, my computer recognizes it and i go into flash tool then i press execute and nothing happens