Brand new, expensive desktop, and I'm already troubleshooting. 2017 iMac, i7-7700k. Installed 32 GB RAM. On first boot, I got a frozen black screen. I held down power and restarted. Worked. At some point in macOS on first use, the computer went to sleep and wouldn't wake up. There is no startup chime on this model at all, so that doesn't help. Took me 30-45 minutes of a combination of attempting unplugging/replugging (e.g., SMC resets) and attempting NVRAM resets with the stock wireless keyboard. I'm not sure why it finally worked, but it did. Prior to that, option-booting, safe mode booting... nothing. So I get everything installed, Boot Camp -> Windows, was playing BF1, and the game hard-locked. Press/hold power, and I'm back to booting to a black screen. I can hear the fan spin up, but I can't get anywhere else. No USB devices connected. This is pissing me off. What am I not thinking of doing or trying?