BIOS problem, ethernet port problem

I've got a problem with my ethernet port, integrated into the motherboard. I have an XFX 8300 Geforce, nForce 730a motherboard. I think the integrated ethernet port stopped working since i installed BIOS update 1.8 over BIOS version 1.6 from 1.7. Unfortunately XFX don't provide updates bellow 1.7 now any more to download and i remember that BIOS version 1.6 was the last version i had in which my integrated ethernet port was working. Is it possible do you think that actually upgrading the BIOS can have some negative effects on hardware, i mean disable them. Because i have tried alot to make it recognised in network devices. The hardware does not appear up in device manager i fear the worst that the ethernet port is genuinly broken, but the motherboard is only less than a year old. Also i had the wired ethernet port working in the past, it's just that for sometime i've been using a wireless USB adapter for the internet. I have selected in BIOS "enable PCI-e LAN" and all other options available that would play a role in the working of the ethernet port. The USB ports bellow the ethernet port all work, and so it suggests that surely the integrated hardware isn't broken.