New Build Not Posting

[FavoringWinter]

I am build a new pc for my brother and when I go to press the power button, nothing happens. No Fans spin, no rgbs come on, and I am wondering what is wrong. (The GPU a placeholder GPU and prices are not accurate to what I got them for)
Full Specs are

PCPartPicker Part List

Type	Item	Price
CPU	Intel Core i3-10100 3.6 GHz Quad-Core Processor	$145.00 @ Amazon
CPU Cooler	Cooler Master Hyper 212 Black Edition 42 CFM CPU Cooler	$39.99 @ Amazon
Motherboard	Asus PRIME H510M-E Micro ATX LGA1200 Motherboard
Memory	Corsair Vengeance LPX 16 GB (2 x 8 GB) DDR4-3200 CL16 Memory	$86.99 @ Amazon
Storage	Crucial P2 1 TB M.2-2280 NVME Solid State Drive	$104.95 @ Amazon
Video Card	XFX Radeon RX 560 - 896 2 GB Video Card
Case	Thermaltake Versa J24 RGB ATX Mid Tower Case	$189.95 @ Amazon
Power Supply	EVGA BR 450 W 80+ Bronze Certified ATX Power Supply	$45.54 @ Amazon
	Prices include shipping, taxes, rebates, and discounts
	Total	$612.42
	Generated by PCPartPicker 2021-03-20 22:53 EDT-0400

I have already tried reseating the CPU and all Power Supply Cables and have made sure the Front panel connectors are plugged in correctly and tried using the screw driver method. We do have a voltage detector pen and it shows electricity all throughout the cables and ports, but when I get to the power switch pins, nothing is detected. I was wondering whether I am doing something incorrectly, or if the motherboard is dead.