Can't get new PSU to work on Omen gaming desktop

[KT-Omen880]

Note: This is my first time changing parts in any computer so of course, I had to screw up somewhere. Also, please assume I'm a complete newbie at this, cause I am. I'm not offended.

My desktop is an Omen 880-130. I installed an MSI  GeForce RTX 3070ti Gaming X Trio, but since the stock 500W PSU is insufficient to power the new GPU, I bought a GameMax 850W RGB 80+ Gold to cover power needs. I am 90% sure I've gotten all the cables plugged in correctly, yet the PSU will not power up. I'm sure the PSU itself is not the issue, as it runs fine when using the inspection tool. There are two avenues I'm looking at to why it's not working:

1. The motherboard's 24-pin port is screwed up.

2. I left one cable unplugged from the motherboard. It is a red-colored cable with two tags attached to it labeled as "USBA MB" and "USBA FIO" (I'd attach pictures to this if possible). I needed to unplug this to get the 24-pin cable through the access hole. Unfortunately, it was left unplugged because I cannot for the life of me attach the cable back into it's port on the motherboard. The tiny prongs move too much and become bent. I tried using a lead pencil tip to get the tiny prongs back as straight as possible but still no luck getting it plugged in. If anyone knows what this cable is used for, please let me know.

Anyway, that's where I'm at currently. Was hoping to install some new hardware and get to playing games more optimally, but I guess it'll have to wait. Thanks in advance for any advice!

[old_geekster]

@KT-Omen880 , welcome to the Community.

I am sorry that you are having problems with your upgrade.  As a newbie you have made one of the most common errors when upgrading the PSU.  I always recommend taking a picture of all of the connectors before disconnecting any of them.  I learned this trick the hard way, also! 😉

You can add a picture to your posts.  You use the camera icon in the header.  If you hold your cursor over it you will see the label "Insert Photos".  Then, you follow the instructions.  Give it a try to see what happens.