Question Just tried making a gaming PC from parts alone. It doesn't seem to work. Please help

[Raspoontang]

I just built my new PC, and it doesn't work. I thought I plugged it in properly, and even looked up what cables go where. My specs are as follows.

Intel I9 12th gen processor
MSI MAG Z790 Tomahawk WIFI DDR4 motherboard
16gb Corsair vengeance DDR4 (X4)
ZOTAC GAMING GeForce RTX 3070Ti
Corsair 1000 watt modular power supply
Noctuna NH-U12A CPU cooler (air)
WD_BLACK SN770 NVMe SSD 1TB game drive (X4)

The computer powers up. All of the fans spin, the rgb on the ram works, and so do the RGB lights on the GPU. But the GPU fans don't spin, there is no display (regardless of which HDMI or Display Port I use) and I can't even get it to a Bios. I can't even install an os, and I have no idea what I'm doing wrong. (Also, none of the USB ports seem to work) If any of you could share your expertise, it would be appreciated.

Currently, I have everything installed. All 4 sticks of ram, both CPU power cables, and the GPU. All I'm using for memory is the 4TB of NVMe SSD. No disk or standard SSD is installed.

 

[EasyListening]

Can you double check that you have the CPU power cables (the 2x8pin connectors on top left corner) plugged in properly? Try reseating them.
Also try booting with 2 sticks of ram, it's just one less variable while you troubleshoot. Re-seating the RAM sticks might solve the problem. Are you sure your ram is verified to be compatible? Check the QVL list.

Maybe you just didn't seat your CPU power supply cables all the way in. It happens.

 

[Lafong]

If the CPU has integrated graphics, I'd try it all without the separate GPU. I'm not sure about an i9.

 

[hotaru.hino]

I would argue go with an absolute minimum build here to troubleshoot: CPU, 1 stick of RAM, and motherboard. No storage, no video card. However look in the motherboard's manual to see if the motherboard has a requirement on which slot to populate. Also I would highly recommend buying these: https://www.amazon.com/outstanding-Motherboard-Computer-Speaker-Internal/dp/B08GKLQWZZ . The computer can beep at you if there's an issue (assuming the CPU is running)

 

[Misgar]

Are the GPU power cables plugged in?