You never mentioned if you're using onboard Intel Graphics or an add-in video card.  If you have an add-in video card, the monitor should be connected to the card, not to any onboard graphics port.  What type port on the monitor is connected to what type port on the PC (HDMI, DP, any port adapters...?). Have you tried using different ports between monitor and PC to see if you can get into BIOS setup? Is monitor being turned on a few sec before PC?  When you power PC on, immediately start tapping F2. Don't even wait until you see the Dell splash screen. And don't wait to start tapping F12 after powering on if you want to get to that menu. If PC won't wake with mouse or keyboard, that could be Windows Power plan settings issues: Open Device Manager and expand list under USB. Double-click each USB entry and click its Power Management tab, if it has one. Uncheck the box "Allow PC to turn off...". Repeat for all USB entries.Now expand list under Human Interface Devices in Device Manager and uncheck that same box for any HID entry that has a Power Management tab. Exit Device Manager when done.Next, open the Windows Power & Sleep screen. Click Additional Power Settings. On next screen identify the active Power plan and click Change Plan Settings. On next screen, click Change Advanced Power Settings.On that last screen, disable Hibernation, Hybrid Sleep, USB Selective Suspend, and PCI Express Link State Management. Save the changes to the Power plan and reboot. Does that fix the wake problem?
My Dell XPS 8920 Desktop PC runs WIN10 Home, version 20H2, OS Build 19042.1415 with Windows Feature Experience Pack 120.2212.3920.0 Following a Clean (re) install of WIN10, I am unable to access the UEFI settings by either of the two usual methods that is: I've also tried other solutions I've seen suggested such as refreshing / resetting the CMOS by removing the button battery and replacing it (with a new one) a few hours later. I want to access the UEFI settings because (1) I want to be able to boot from a DVD if my system crashes - to load WIN PE or Macrium Rescue DVD discs - this is necessary if I ever need to restore my weekly Macrium Clone and (2) I want to be able to change other UEFI settings like "allow devices to wake WIN10 from sleep" and check power goes to all USB sockets by default. I am thinking if I ever need to - if I disconnect the SSD drive to prevent Windows loading, will the PC then start the DVD drive and thus search for an operating system (or Recovery DVD, Recovery USB) to start even though I've been unable to change Boot Priority Order through UEFI-BIOS. Any suggestions on what more I can do would be appreciated.
XPS 8920, how to access UEFI settings?