PC not connecting to a working wired network

Hey guys and girls, hoping for help with a very frustrating problem.

A week ago my primary desktop PC lost its connection. Since then, I have actively troubleshot it and restored the connections multiple times. Today I'm in the middle of some work and the PC reboots itself and upon reboot the network is down again, but only for the main PC.

I'm using an ASUS P7P55D motherboard and have flashed to the most recent stable bios and have updated to the most recent drivers for the realtek PCIe network card that the cord is plugging into. I've also replaced the physical cord.

Getting pretty frustrated and thinking about formatting the whole thing just to be done with it. Does anyone have a few ideas of additional things that I can check or update before reformatting?

Another wired desktop and the wireless laptop are both using the connection just fine. And I did switch ports on the wires to see if it mattered (it didnt)

The BIOS update and driver change were enough to fix it last time.

I'm drawing a blank now. Thanks.

have you tried adding a separate network card?

maybe the onboard one went bad

Haven't tried a separate network card, would need to purchase one.

Not overclocking intentionally - I downloaded a stupid app by ASUS called CPU Level Up that pushed overclocking settings that I wasn't expecting. I uninstalled immediately but found yesterday that there were still components running that I had to modify to remove. If I'm overclocking now it is through ignorance, but I don't think I am.

I have rolled back drivers. It worked once. Wouldn't let me roll them back the next couple of times it happened. Today i checked and it let me again (wierd, I made no driver changes in last few days) but this time it didn't help.

Sounds like I'm going to need to look for a network card.