Glad you got it working. Can we assume you applied fresh thermal paste between the CPU and heat sink? Check in Windows Event Viewer and in Windows Reliability Monitor to see if either of them logged an error when PC froze.   Also look in Windows Update history to see if an update failed around the time of the freeze. There are recent BIOS updates for the XPS 8930, and I wonder if Windows Update tried to install one of them and that caused the freeze...? The latest BIOS is 1.1.26 with new Intel security patches . If you want to update to this version, put the BIOS .exe file on an empty USB stick (FAT32 format). Plug it into PC with power fully off. Then power on and tap F12.  When the menu opens, select the Flash Update option. Tab through the Update fields and when you tab to the Start button, check top left box for current BIOS info and top right box for new BIOS info. Assuming both are ok, click Start and leave PC alone until it's safely back at  your desktop. It will shut down ~3-4 times while working on the BIOS update, and may look like it's not doing anything, but just leave it alone... After PC boots to desktop, restart and tap F2 to open BIOS setup. I suggest you disable UEFI Capsule Updates to prevent Windows Update from attempting to install any new BIOS. It sometimes installs the same BIOS on top of that exact same version even though it's already installed....
Brand new, but never opened the box until a month ago (expired warranty). It booted up the first few times and I was able to update and install Win 11. After that it failed power up with a single flash of the power light most of the time. Once when it did power up, I ran thru all the BIOS diagnostics and everything passed. It will no longer power up at all. I just ran the BIST diagnostics and it powers up stepping thru disconnecting and reconnecting every cable until I got to the ATX-CPU 4-pin Molex. Plug that in and it fails to power up. Any idea if this is a power supply failure or a CPU/motherboard failure?
XPS 8930, won't power up