Tablet doesn't respond to touch neither when mouse is plugged in, at all Recently my Colorfly E708 Q2 tablet stopped working. First time this happened a message box popped up, with the text "Unfortunately System UI has stopped" or something like that, but i wasn't able to close the pop-up box, because the system didn't respond to any user interaction. So i decided to restart the tablet.

Display doesn't work, doesn't respond to touch, nor to mouse when connected through usb. I need to mention, that when the mouse is connected, the mouse cursor shows up on the screen, and does even track the movements of the mouse, but as i said, it does not respond to clicks. 

I've seen on some forums, that the only thing that would help to fix the tablet would be if i'd replace the firmware. Sadly, since the developer options aren't enabled on the tablet, i was not able to reboot into a boot menu. The device has no physical sound buttons (only power, home and reset) , so what would work with other devices, doesn't work in my case.

Is there any way to fix the system ui, or re-flash it in any way? I mean it was cheap, but it worked for me so I don't really want to buy a new one.

UPDATE:
I plugged in an USB keyboard, but the only thing I could achieve was to adjust the volume of the device.
+ A new box popped up, with the message "Launcher stopped working", with two actions: wait and close. Of course its not possible to select either.

Documents:
Tech Specs
User Manual
NOTE: THIS WILL FACTORY RESET YOUR DEVICE!
To fix this problem, first shut down your tablet. Boot into the bootloader by booting up regularly, but holding down your power and volume up buttons when you see the logo.
If you haven't installed fastboot, do that first.Then, go to the command line and type in

fastboot oem unlock

Then, find and download a factory image, then run

fastboot flash /path/to/factory/image.zip
fastboot oem lock
fastboot reboot

Hope this helps!