[SOLVED] EZ Debug light, tried everything I can think of - time to RMA processor/mobo?

[HambonePlayer]

Building a computer for my dad as a holiday gift, and I'm tearing out my hair here - here's the build, or at least as close as makes no difference:

PCPartPicker Part List

CPU: Intel Core i7-11700K 3.6 GHz 8-Core Processor ($342.99 @ Amazon)
CPU Cooler: Cooler Master MASTERLIQUID ML240L RGB V2 65.59 CFM Liquid CPU Cooler ($73.06 @ Amazon)
Motherboard: MSI Z490-A PRO ATX LGA1200 Motherboard ($129.99 @ Newegg)
Memory: G.Skill Trident Z Royal 32 GB (2 x 16 GB) DDR4-3600 CL19 Memory ($159.99 @ Newegg)
Storage: Western Digital Blue 2 TB M.2-2280 Solid State Drive ($179.99 @ Amazon)
Video Card: MSI GeForce RTX 2060 SUPER 8 GB VENTUS GP OC Video Card ($929.99 @ Amazon)
Case: Fractal Design Meshify C ATX Mid Tower Case ($99.99 @ Amazon)
Power Supply: Corsair RM (2019) 750 W 80+ Gold Certified Fully Modular ATX Power Supply ($94.99 @ Newegg)
Operating System: Microsoft Windows 10 Home OEM 64-bit ($108.78 @ Other World Computing)

Got everything plugged in and started up, all fans/lights working, got into the BIOS no problem, temps looked fine. Got an error the first time I started installing Windows ("this PC doesn't meet the hardware requirements," so I turned on TPM in the BIOS) Then started installing Windows again, everything worked OK for 5-10 minutes, and it shut down about halfway through.

Now, whenever, I try to start it up, all the fans and lights start up, but I get no display output and there's a CPU light on the motherboard's EZ debug panel. (White light, for the record.) The keyboard's caps/scroll/numlock lights go on and stay on, and the reset button doesn't work.

I have tried: Checking and replugging all the power connections, re-seating the CPU, re-seating the cooler module on the CPU, moving RAM sticks around and testing one at a time, pulling out the GPU and trying it with integrated graphics - same result, every time.

I would love to know (1) why it started up OK to begin with (2) whether I need to swap in a new CPU or (god help us) new mobo to get this thing working correctly. Any input deeply appreciated, and I hope this is the correct forum.

EDIT: I forgot, I also popped out the CMOS battery, waited for 30 sec, and replaced it as it was.

 

[HambonePlayer]

UPDATE - Fixed it. Turns out I didn't use the goofy internal USB hub that came with the cooler. Follow the directions, kids, and watch a video from the OEM if the printed directions suck.