Based on not seeing the bios post then you have a hardware failure. You don’t even need a hard drive to get the bios screen. You do need a good motherboard, power supply, CPU, and Ram. You could try unplugging all drives in case one has a short or the power supply is weak, but that is unlikely.
There’s just the one HD. Has space for 6, full size!
Definitely will try one RAM stick at a time. That’s easy peasy.