How to get an external CD to boot before USB? Acer Aspire 3 Laptop

[April]

Getting an external CD to boot before USB
I want to boot Xenialpup64-7.5 from the Live CD .
I have EayOS only on my laptops hard drive atm and the drive was formated originally as ext4 then the new iso dd'd onto it with Barry's EasyDD frontend.
My laptop is an Aspire 3 Model N19H1
Normally the F2 and F12 get into that area but I try bootup and hold them down or tap them and it just goes straight to EasyOS Dunfell
Somewhere when running EasyOS it cropped up as a choice there but I can't find that leadin again.
I'm guessing there will be a way to get into the normal hard drive etc setup menu but I don't know which key to hold down as I power on and get into the normal F2 and F12 screens which are built into the laptop.
I've looked for a manual but they seem scarce/nonexistent.
I also want to get into the laptop password area to change the password but don't see a way? I put a password into EasyOS and am using it now . My problem is I don't like it and want to change it

Anybody know how to do this?

[Misaligned]

Have you tried the DEL(elte) Key?
Maybe F8 or Esc.

Good Luck

[bigpup]

If this is a computer that did work pressing F2 or F12 got you into the bios setup.

Make sure you are pressing the key just as power is applied.

[April]

Thank You both.
Problem partly solved . I plugged a desktop keyboard in and it took over the keyboard entry. Then hitting F2 and F12 worked to let me in . While there I attempted to change the password which it seemed to do.
I found the Function keys on laptops now have dual uses. In the F2 they can be set as Function or Media and it was set on Media. I changed it to Function.

None the less when the CD is chosen in the boot up process it still will only load from the hard drive and not the usb drive (with CD reader connected) selected?

Then I noticed though that in EasyOS, once a password is entered ,still asks for the old password, so I guess as its used to encrypt the source drive, its needed to un-encrypt it.
I would like to change that and I think Barry has provided for that. I just have to find it. I'll edit here when I find it. EDIT nah can't find one on Easyos

I found a manual of sorts for this cheap machine (AUD $350) and I'll put in on my MEGA site because its too big to put here. You can preview it there without d/l if you wish .https://mega.nz/file/T5lwCD4b#o3AkoRNG6 ... rDfD-SMtRo

These are the key descriptions from the above manual , screenshots would work but by the time I reduce them to the size required here you cant read it and it takes hours!
Noteable.....

3 Battery reset
pinhole Simulates removing and reinstalling
the battery.
Insert a paperclip into the hole and
press for four seconds.(on back small hole)

Lock keys
The keyboard has lock keys which you can use to turn keyboard
functions on and off.
Lock key Description

Special keys
Your computer’s keyboard includes keys that activate special
functions. The function of each key is clearly marked with an icon.

Sleep Puts the computer in Sleep mode.
Flight mode Turns on / off the computer's network
devices.

Display toggle Switches display output between the
display screen, external monitor (if
connected) and both.
Display off Turns the display screen backlight off to
save power. Press any key to return.
Touchpad toggle Turns the built-in touchpad on and off.
Keyboard
backlight toggle Turns the keyboard backlight on and off.
Function varies depending on
configuration.
Speaker toggle Turns the speakers on and off.
Volume down Decreases the sound volume.
Volume up Increases the sound volume.
Scr LK Scroll Lock
Turns Scroll Lock on or off.

[don570]

If you can get to the EasyOS boot screen then choosing '3' option will wipe out data folders and start pristine.
I'm not sure what this does to password storage since I never use a password.
____________

[April]

Thanks ,
I have tried repeatedly with the laptop but they are obviously made to Microsofts specs if they want to run windows .

Microsoft have been bashing Linux from its inception as a competitor.

Working on it and can get it up in the boot window as an option now but it still will not load even with "secure boot" off.

[mouldy]

Might try PLOP boot manager in one of its iterations. Some older laptops when it was truly hit or miss whether it would boot from any usb, if you wanted to boot from usb, either thumbdrive or dvdrom, then that was the ONLY device you wanted plugged, cause "external drive" was only alternative boot option. It didnt differentiate between multiple external usb options. On those before they could boot from usb natively, then PLOP was best bet. Or sometimes you could mess letting it start booting from hard drive and have your bootloader then switch to the files on usb. Kinda depended on the computer.