External monitor worked, but now does not!

Hello all, I have never posted any questions or replies to these types of sites before, but here it goes. I own an "Unbranded" (that IS the OEM) 10.1" tablet that I upgraded to Win 10. I seem to have good luck up until now, I used win+p to set an external monitor to extend display, but ever since I unplugged the monitor to move it, the thing has not worked. I also went through control panel, checked display settings there, and also right-clicked desktop and clicked display settings there too. Nothing is working to get the monitor working again. It gets power and turns on fine, but not extended display like before. I tried and failed to open settings on the monitor itself, I also checked the drivers for the graphics, but no luck. I think I tried everything and even went to Microsoft for help, and that was pointless! So, any suggestions would help greatly!

Thanks!

Try these key combinations and see if one will work:
WIN P P (may need to do this several times)
Fn F4
Fn F5

So, I have tried FN F4 and FN F5, neither worked and when I typed WIN P P it shut off my on-board screen and I had to manually shut down my tablet then reboot. The screen came back on, but the external display extension is not working though. I will double check the drivers, because another user had that issue and updated drivers fixed that.

The second monitor must be connected and switched on to be detected. If it is a TV you should change the source to PC or VGA to be detected. Make sure you have latest graphics drivers from manufacturer (not Microsoft).