You may need to clear the password by shorting the two solder points on the motherboard. If you have the invoice for the comptuer, Acer should be able to give you the master password for UEFI. What software did you use for creating a bootable USB flash drive? What windows media did you try to boot, Windows 8? Windows 7 media cannot boot on a UEFI computer.
This computer dual boots with Windows 8 and 10?
Acer won't help with bios passwords unfortunately - I guess they put that shorting information in the manual. It just seemed rather drastic to me, never really expected to have to start opening the unit up! I'm only looking at doing the disk change to give my sister my drive (her's failed) and I get to treat myself to a new shiny thing!!
I tried creating a USB of the clnpwd.zip download - it comes with the HP usb disk storage format tool v2.1.8 (it's a dos boot key creator) and is supposed to make the acer clean password utility available through clnpwd.exe on a boot into dos.
However my unit will not boot from any of the USB ports. I tried a win8 and win10 dvd but it won't boot from the dvd drive either, which is bizarre, even when I removed the hdd it just reported no bootable device and ignored the USB and the DVD drive. I can't understand this since normally all storage/boot devices are usually listed in the bios (which I can't see).
The windows dvd's I created are good as I've had to use them this week to recover my sister's machine when her disk started getting bad sectors and failed to start.
I think I agree with you that I'll have to short that Jcmos jumper. In those instructions, it refers to a cp.exe utility which looks simple - do you have any idea where they might be found? They seem to be listed in the collection of "flash utilities" but I'm not aware of these tools. My machine has had a bios update downloaded from the acer website and recommended for my specific model, but it was just an exe file and no interaction was required.
One other detail. This was/is a win8.1 unit. I've created a small partition on its drive and installed win10 onto that (to test it out before I do the full upgrade). Since then, booting up gives the UEFI screen to choose which windows o/s to boot into (very neat too). Before, it would simply go straight to the windows splash screen for win8.1 after displaying the Acer logo on a black screen for about 12 seconds.
Could this have affected the ability to boot from different devices?