Can't Change From Legacy Bios To UEFI

[#1]

Hi, I recently fixed my Acer ES1-111M-C3CP, after accidentally removing its software. I installed Ubuntu 14.04, as that was the only software I could install. in the process of doing this, I changed the boot mode from UEFI to Legacy. Now, I can't change any settings, apart from the date and time. I shall provide pictures. I just want to know if it's possible to return to UEFI boot mode. Thanks in advance!

[#2]

I don't know for sure but I suspect this is because the BIOS is checking the partition table type on the hard disk to see if UEFI can be enabled. I suspect that the your hard drive has a MBR (Master Boot Record) legacy partition table which is being detected by the BIOS and preventing UEFI from being enabled.

For UEFI to boot a hard disk it must have a GPT (Guid Partition Table) partition table.

[#3]

Um..

Well, we I'm guessing we need to change the BIOS boot from Legacy (or some other words like CSM Boot) to UEFI, but it's not possible.

According the booting section of https://wiki.archlinux.org/index.php/Acer_Aspire_E11_Series , we could enter the efi boot by pressing "F2 at the boot splash screen to enter the EFI setup, then select the Boot tab."

If that doesn't do anything, I would just take out the cmos battery and put it back on - which should reset any BIOS configurations and return the BIOS back to factory settings.

Scratch that, I believe mikelahey is right, a model of an Acer laptop is designed for you to have to install efi Windows 8 (with the GPT table as I'm pretty sure MBR wouldn't work). 

http://community.acer.com/t5/2014-Archives/No-legacy-option-in-F2-setting-Just-UEFI-Acer-Aspire-E1-4...

Though you ought to ask over at the Acer forums where someone there can help you specifically for their products. I myself don't own an Acer laptop.

[#4]

So I changed the partition to GPT, but now it just comes up with a black screen saying:

'Error: no such partition.

Entering rescue mode...

grub rescue>'

Am I supposed type some sort of command here? I know I changed the partition and that's why this is happening, but now I can't boot anything...

[#5]

Have a read here.

Insert an EFI only Ubuntu USB stick and see what boot options you get.