HP Z2 Mini G9 will not boot up: power light comes on, no display, then goes out after 70 seconds

[lovelychum]

I did a Windows 11 upgrade and shut down. The following morning the computer would not start. The power light comes on but nothing happens and the monitor cannot detect anything. After about 70 seconds the power light goes off. I've unplugged, re-plugged, hard reset, checked the cables, no luck. At one point I tried restarting it over and over but it got really hot at the back.

I took it to a local IT guy who tried it on his monitor, and he said it looks like it's trying to do something, but he won't look at it because it's still under warranty. Any thoughts/help would be much appreciated, especially if it saves me losing data on my hard drive (I'm self-employed and last backed up in April 😞   ).

Thank you.

[gary_elliott]

I was able to get the display working by connecting to the mini-DisplayPort.  When mine came up, it was prompting for the BitLocker key. After entering the key, it seems to work OK now.  My normal DisplayPort connection works again as well.  Kinda weird.

[JosephStewart82]

Exact same day, exact same issue for me. Weird. I'm waiting on mini display chord to try out suggestion below. 

[Knewcomb6]

Wow. Same exact thing happened to me. I went to a local parts store and bought a mini-DisplayPort and was able to get display again. I was also prompted for my BitLocker key. Everything seems to be working fine now. I have not upgraded to Windows 11 yet. 

[dhiltz]

Yep -- exact same day, exact same issue for me too. The mini display cable allowed me to see the Windows prompt for the BitLocker key.  Thankfully this was easy to obtain, following the Microsoft link that was provided. 
Appreciate everyone's posts!  They convinced me to go buy a mini display cable.