HDMI connected on Google Nextbook 8 when no HDMI connected

Recently, my Nextbook 8 has been acting oddly. What it does is switches into HDMI mode, though there is no HDMI cable plugged in. I first noticed this on Sunday. The screen was refusing to rotate, even for apps that required a different screen orientation. When I figured out that HDMI Switch was on, I turned it off and that fixed the problem. Temporarily. Now, the screen flashes frequently as it "connects" and "disconnects" from HDMI, which makes using it next to impossible. Sound stutters when it does this, and if it's "connected," I can't watch videos on it. I've never once connected HDMI to it, and I take care of my electronics. I've never dropped it, I have anti-virus on it that finds nothing wrong, and I haven't downloaded any new apps. I've found nothing online to help me solve what could be causing this, though I've been searching since Monday. All problems I've found through searching have been "HDMI not connecting" issues instead. Any help would be greatly appreciated in this matter.