Here are your details rephrased:

The PC case model is B550 Aourus Pro AC Ryzen 7 5800X. It features a 3600MHZ Radeon Saphire 6750XT graphics card, an EVGA 850 GT PSU, and supports M.2 slots with Samsung 870 EVO. The system uses a WD SN850 motherboard and comes with a 2TB SSD (HDD).

Recently, about five weeks ago, I attempted to power on the machine but found nothing working. I verified the power outlet, connections, and fans—nothing was amiss. I tried replacing the PSU and motherboard to rule out those issues, but the problem persisted. I contacted Best Buy, who confirmed it was functioning properly. I disconnected all fans and storage drives, then received a call saying everything was fine. Upon returning home, I saw some wires still unplugged, but the system started working. After updating the BIOS and checking for errors, I noticed all SATA ports were missing.

I considered that the ports might have failed, or that the drives wouldn’t work with my current board. I planned to install an expansion card using four M.2 drives. However, while playing games last night, I turned off the PC. This morning it still wouldn’t power on for some systems, and it didn’t respond at all. I decided to try a fresh setup again—this time it worked.

Someone suggested checking the GPU and CPU connections, specifically mentioning the Radeon Saphire graphics card and Ryzen 7 processor. The situation remains unclear, but I’m hoping this will help.