Hi Esteban Callejas,
Thank you for your patience. It should like the BIOS display settings got disabled when things were being changed. I would recommend not going into the BIOS only if you really need to change something.
You might have to reset the BIOS by taking apart your Laptop case and then trying to find a CMOS - BIOS battery that you can remove.
PLEASE TURN OFF YOUR LAPTOP AND UNPLUG IT FROM THE POWER SOURCE BEFORE OPENING THE LAPTOP UP.
1. Open Laptop with proper tablet and computer tools.
2. Try to locate the CMOS - BIOS battery.
3. Disconnect the Laptop Main Battery.
4. Take out the CMOS - BIOS battery and let it remain out of it's socket for about 30 minutes to an hour.
5. Put back the CMOS battery and reconnect the Main Battery for the laptop.
6. Put together the Laptop.
7. Power it up to test if that solved the screen issues.
Please also see photographs below to see what the Main Battery and CMOS battery looks like.
Please follow the steps below to restore your device to the original state.
1. Download Rufus format partition tool from the link below.
2. Plug in an empty Flash Drive that has at least 8 to 16 GB free into extra computer or device.
3. Run RUFUS and select the following parameters.
A. Device - Select your USB flash drive
B. Partition Scheme and target system type - GPT partition scheme for UEFI computer
C. File System - NTFS
D. Cluster Size - Leave as Default
E. New Volume Name - Winpe - it must be named this otherwise it won't work properly.
See photograph below as reference. Please make sure you uncheck the box that says – create a bootable disk using ISO.
4. Download the Recovery drive for your device at the link below.
5. Unzip files and then move all files in folder (should be at least 10 to 20 files and folders) TO the formatted FLASH DRIVE.
6. Turn off your Device and plug in your OTG cable and the Flash drive. Please use a USB 4 port HUB so you can use a keyboard if necessary.
7. Turn on device and constantly press the ESC button to get into BIOS.
8. Go to the last menu option and in the boot override section arrow down to "UEFI: <Thumbdrive>" and hit enter. If your device does not show boot override, you will need to manually set the Thumbdrive as first in priority under the boot options, then save/exit. It should then boot up and perform the flash and shutdown.
9. Remove Flash drive before restarting.
PLEASE LET ME KNOW IF THIS WORKED FOR YOU.
There's no such battery for CMOS in Flex note III