I Have a Nexus 7 and recently I found that I needed to use ADB for something and I had used my Nexus 7 with ADB on this computer before (thats how I installed KitKat) but whenever I connect my Nexus now it says that is not configured correctly and when I attempted to install the ADB driver it said windows encountered an error. I am currently running windows with Driver verification disabled and on test mode. I am also running windows in test mode so that it wouldn't block the driver. I have tried every driver possible from the one in the SDK to the intel android adb driver and even PDAnet. I have checked inside the driver file that it is properly registered for my nexus 7. I am running Windows 8.1 on my computer and android 4.4.2 kitkat on my Nexus 7. Could anyone please help?