Question Newly upgraded system not powering on

Jul 17, 2019
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I have just installed a new motherboard, cpu and ram into my pc and when I try to switch it on nothing happens.
I believe I have eliminated the possibility of a PSU issue as it was working fine yesterday evening and the fan spins when I turn it on (on its own). The power button seems fine as when I manually bridge the power switch pins on the motherboard nothing happens.
If it is of any use, the motherboard I installed is the aorus b450 elite, cpu is a ryzen 5 2600 and the ram is 16gb of corsair vengeance.
Also to note, the aorus logo lights up for a split second the first time the power supply is switched on after being unplugged for a while.
Thanks in advance