Factory reset Windows tablet without keyboard and password

I received a Windows 10 tablet as a gift. The tablet is Prestigio multipad visconte V, I don't know the password as the tablet was second hand. When I try to reset it using Widows restore, it says there is not enough space. I tried using a USB drive to reset it that way but the USB drive is not recognized, same is with the keyboard. Also I tried to enter commad prompt but is asks for password. To enter boot menager you can hold power on and volume up button, but when I do that it brings shows me: entering dnx mode waiting for fastboot command...

Question by bacan on Super User, licensed CC BY-SA. We show a short excerpt and link to the original thread as credit.