I spent the better part of Saturday, Sunday, and a few hours this evening trying to get to the root of a problem I've been having with my Yiynova MVP10UHD tablet screen. The express keys or hot keys weren't working at all. The pen was fine though. Pressure sensitivity in SAI was great, but I couldn't use any of the screen's built-in hot keys.
tl;dr: Make sure your computer name and user name are different.
For background, I recently upgraded my laptop and desktop to Windows 10 and did a clean install. In doing so, I renamed my desktop to XYZ. [In retrospect, it was probably a bad idea to name my primary user account XYZ too... More on that