I don't know where to turn next for an answer.
I updated my drivers, to the ones suggested by dell and I also updated to the latest bios.
Re-booted and the computer wasn't seeing my hdd so I checked the bios to see if anything had changed (nothing had) so I re-booted and tried the automatic repair the machine suggested, it asked me if I wanted to boot by using uefi safety boot so I gave it a try and now it doesn't even reach the Dell splash screen, no beeps, no bios on screen.......nothing, the screen is just blank.
Ive tried a few bits from other models but cant get the machine back.
Can anyone talk me through how to get the machine back so I can at least boot into the bios please?
As an update to this problem, out of desperation after trying everything, I replaced the monitor with another one, even though the monitor I was using worked perfectly well. And as soon as I plugged it in the dell splash screen came on and it booted into the bios. So I then plugged the original monitor in and the dell splash screen was there too. so I have no idea what the problem was but its all sorted now.