Hi to all,new to linux and the forum.
I have an acer aspire 5315
Had Zorin 16.1, was always very very slow
Upgraded to 17 with usb download
All seemed to go well, all files checked, no errors
Shut down, restart and failed to boot
Message 'no bootable device found '
Will only boot from usb
manually set boot to harddrive, no joy
I researched forums but don't understand a lot about terminal.
All seems to point to BIOS fault
Have tried to repair grub2 in Gparted
Have tried Boot Repair, Bios info summary is at http://sprunge.us/Db6n5D
It says to 'disable BIOS-compatibility/CMS/legacy mode', 'set BIOS to boot in EFI mode' but cannot find that ability in BIOS
Before the start up there is a grub bug error showing, although i think that has been there a long time as it has always been a bit slow.
Any pointers would be greatly appreciated

You might post more details on the age of the computer to get help. This is because you mention in your post you can not find and reference to UEFI in your BIOS. Upgrades are usually done through repositories so did you download a new 17 Zorin iso, create a bootable usb and reinstall Zorin? Did you format the / filesystem? What actually happens when you set the computer to boot from the hard drive? Blank screen, error message and if so what?

Not much point in posting the above if you don't post the actual error along with it.

You need to verify that your computer is UEFI capable. Any computer manufactured after 2012 should be and you should see references in the BIOS under the Boot tab. You have booted the Zorin usb you used to get boot repair in Legacy/CSM mode and the suggested repair is to do a UEFI repair so you need to verify your computer is EFI capable and, if it is boot in UEFI mode.

You have a GPT drive on which installs are commonly made in UEFI mode. With Linux, you can do a Legacy/CSM install on a GPT drive by installing Grub code to the MBR and creating an unformatted BIOS-boot partition. You have both but you also have an EFI partition.

Was your original install of Zorin 16 a Legacy/CSM install and when you installed 17, did you boot and install in UEFI mode? Or perhaps the reverse?

Hi Yancek, thanks for the response.
I did download the iso from Zorin site and installed from a usb.
No I didn't format the file system, I just followed the prompts from the download.
When I try to boot from the hard drive I get ' No bootable disk found, insert disk and press any key' on a blank screen.
If I don't press enter at install screen from the usb after turn on I get the following
[ 0.427900 ] ACPI BIOS Error (bug):\ l_SB. PC10._OCS: Excess arguments - ASL declares 5, ACP-I requires 4 (20230331/ nsarguments -162.
I can't see where to verify UEFI capability in the BIOS.
I don't know what type of install 16 was, I seem to remember it was an upgrade from an earlier version of Zorin, must have been downloaded also.
As far as the Zorin 17 download I just followed the recommended suggestions on the install screen.
I have uploaded som photos of the BIOS .
As you can see I don't know a lot, I am on a very steep learning curve.
Thanks again for taking the time to respond.

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Did you look under security or main?
This is the first problem I see:
The EFI flag/type needs to be removed from sda3.
Another possible fix is to copy sda2 efi/ubuntu/grubx64.efi to sda2 efi/BOOT/Bootx64.efi

I'd recommend that the OP check ACERS' support website for BIOS upgrades as there may well be an updated version of the BIOS for the model of their machine which could resolve issues such as this one.