Black screen

Were you trying to run Ubuntu from the USB, or were you booting from USB to install Ubuntu on the hard drive, replacing Windows?

If you were trying to install Ubuntu on the HDD, did it actually install and now it won't boot? Or did it never get installed?

How did you change to boot from USB?

I tried booting from USB and it didn’t work

So I turned off safe boot and tried again that is when black screen and now nothing

Light on power button turns white USB blinks and if I put a CD in drive I can here it spin and fan also works

Just did Dell system check of all hardware and everything was OK

I JUST WANTED TO TRY UBUNTU TO SEE WHAT IT WAS LIKE

HOPE YOU CAN HELP!!!

Is this PC connected via the HDMI-OUT port to an external monitor?

Are you seeing the black screen when you try to boot from the Ubuntu USB or when you boot Windows normally from the internal drive?

Have you tried pressing the Screen On/Off button (#16) on the right edge, just about the Power button, and/or the two Brightness buttons (#17) above the Screen button, when you see the black screen?

Note: It may take several presses of the Screen On/Off button to cycle through options. So press once, wait a few sec and if no change, press again and wait, and maybe press a third time and wait...

If you're able to run diagnostics, I assume you can see the screen, at least until you try to boot Windows. Is that correct?

Reboot and start tapping F2 to open BIOS setup. I assume you'll see that screen. Use arrow and tab keys to navigate around and look around for boot options. Make sure Windows Boot Manager is first option or move it to first place, if necessary.

Then look around for the option to reset BIOS to the default settings and follow the prompts, if any, to reset to defaults. Be sure to save the changes before exiting setup and let PC boot...

Glad you got it sorted. Removing the motherboard battery is another way to reset BIOS.

I presume you reinstalled it afterwards...