What does your q-led tell you?
Try re-seating the ram and check all your power supply connections. After checking those, the next logical purchase would be ram, a cheap GPU just for testing and finally a CPU.
Lets review. PC will not power on at all. You're seeing the RGB's on the board, so you have standby power to the board. You said you tried jumping the power switch pins and nothing happened correct? Watch your fans and make sure. You're not seeing a quarter turn of a fan or anything when you hit the power button?
Do you hear any sounds from the PSU when you try to start the PC?
I'd say it's time to breadboard it. Pull the board and put it on the motherboard box. CPU and cooler only installed. 24 pin and 8 pin to the board, no GPU. See if it powers on like that.
Make sure the CPU fan is properly plugged in. I would even try testing the cpu fan header with a different 4-pin PWM fan and try turning it on for just a second to see if the cpu cooler fan is good...
Some mobos wont turn on if theres not a CPU fan installed.
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