Specs:
Asus K8N-E mainboard with nForce3 chipset onBoard ethernet controller
Seagate SATA 120gb
Athlon 64 3200+
Intel PRO/100+ Ethernet Adapter
Windows XP SP2
(video card and tv tuner)

Problem:
I had left my computer on overnight to seed a torrent and when I woke, the computer had froze trying to go into standby. I guess this was caused by the fact that Azureus was running in the background. Anyway, I manuall restarted the computer and when it started, I found out the onboard network card(nVidia card) was not working. So I plugged the ethernet cable into my spare ethernet card(Intel card) already installed. The spare was working fine. I then figured out that my onboard card was giving a 169.x.x.x IP Address so I googled it and found some solutions. I played around with them and eventually trying the Winsock Fix which didnt work and just froze. I then tried to unistall the device and then reinstall it but apparently windows doesnt like it when I attempt to do that. It would just freeze and I would have to manually end the operation through the task manager. Finally through a combination of shutdown, System Restores, and attempting to reinstall the drivers the nVidia card worked again.
However,
The same problem came up a couple days ago and I have tried replicating my steps with no success.
Here is a list of the things I have done:
-Attempted to unistall and reinstall the nVidia card(no luck) + changing drivers to new/old
-Winsock Fix
-Static IP on the nVidia Card
-Shutdown and restart

Here is things I know wont work:
-restarting the dhcp server
-the cable is fine it works with the Intel card

Here are things I want to avoid or can't do:
-System Restore( it appears that system restore removes data that has been added since the restore date and recently placed a good amount of music onto my computer and I would rather not lose it)
-Safe Mode (I can't boot into safe mode, I try and it won't let me, it just restarts itself, I have no clue why it doesnt want to)
-Manually fixing the winsock-risky and i doubt it will work

Oh one more thing,
I have a dual boot with Fedora Core 4, the network card seems to not be working in Linux either.

Thanks in advance.

System Restore does NOT destroy data saved to the hard drive. It undoes any registry changes since the date of the restore point. ie programs (installed after the date) may not work but hard data should not be lost.
Quite frankly it sounds like you have a corrupt windows installation. But being that the port doesn't work with fedora either leads me to believe that the drivers are corrupt or that bios has lost the connection. First I would try to flash the BIOS to a more recent version (if available) or to the current version again. You can also clear the cmos to see if that fixes the problem. Also check in bios that the port is enabled (dumb but possible).
You should be able to access safe mode, which is why I said it could be windows. Check each of these possibilities.

I think my Windows XP installation may not be booting into safe mode because of a driver problem. I doubt that it is a corrupted install because it worked fine for sometime before this event

Windows can become corrupt at any time. Consider if your memory chips had a bad sector and windows was writing data to it. Windows will not know the sector was bad and then the data it wrote to it is lost. Windows is now corrupt because data was lost. This is an extreme example but it still applies. Just because windows was working all along does not mean it cannot get corrupted. Malicious code does the same, a virus does the same, and in some instances spyware does the same. I still say to check the other things before you conclude windows is corrupt.

Problem Solved!

I cleared the CMOS on the motherboard and the ethernet is functioning perfectly, it even got rid of the hang ups when changing network settings.
Thanks a bunch for the help, it is greatly appreciated.
Cheers!