Unable to boot from USB drive

[aajax]

I'm in the process of setting up a new HP Omnidesk computer that I just acquired.  I've now completed the initial Windows 11 setup.  I've been using Windows since it's inception and have been relying on Windows PE for decades to capture installable images of the boot partition.

Windows PE is normally run (i.e., booted) from a USB drive.  However, I have not been able to even boot into the BIOS on this computer.  For example, I tried performing the operation described in HP Desktop User Guide on this page but the computer proceeds to boot into the just installed Windows 11 System.  It might also be worth pointing our that I do have the Windows 11 Installer which would also need to be started in the same manner.

This is more important to me than it might be to most users because I run my computers in multi-boot which requires making changes to the BIOS.  Fortunately, I am still within the window of time where I'm allowed to return this computer if I cannot get to function properly.

However, it does look like I need some help in order to get this to work.

[DFWTechGuy · Accepted solution]

Have you tried pressing Esc repeatedly as soon as you turn on the computer? On many HP desktops, this opens the Startup Menu, where you can press F10 to enter BIOS Setup or F9 to choose a boot device. If Windows starts too quickly, you can also try going to Settings > System > Recovery > Advanced startup > Restart now. Then select Troubleshoot > Advanced options > UEFI Firmware Settings if that option is available.

Once you can access the BIOS, check the boot order and make sure USB boot is enabled. Also, what's the exact OmniDesk model? The available BIOS options can vary by model.

[aajax]

It looks like the Model # is MO2-127c and the Prod # is BP5E2AA.

Yes, repeatedly pressing esc as soon as start light comes on did bring up a screen where various selections were offered.  One of these was called "Please Select Boot Device" using F9 key.  This did bring up a screen where I boot my WinPE USB drive.  This looks like what I expected and should be able run DISM command for creating the image file I want.

Thank you!!!