Need Help with Connectivity Issue

[deathsupport]

Hi guys, long time reader here and now I'm stuck with a problem of my own.
I recently left for one week on vacation. Before I left everything on my desktop was working properly.
When I came back and booted up I noticed that my computer had no Internet access. In fact it wouldn't even ping the default gateway, my router.
I hooked up my laptop to the router and it has an Internet connection (on my laptop right now).

So now I'm confused. I tried reinstalling drivers several times (drivers from the CD and the latest drivers on the Asus website). As a result of my last driver installation, my desktop can no longer ping the loopback address. It fails to acquire a network address, even though I have it manually set in the local area connection properties. It also didn't work when I plugged my computer straight into my modem (cable Internet) and had it automatically get an IP.

Furthermore, whenever I try to change the IP address in the local area connection properties box it tends to freeze up. I had a similar situation when I tried to uninstall the nVidia drivers. Also, the Activity/Link LED near the RJ45 port stays solid as opposed to blinking.

I've never encountered a problem like this and maybe someone can help. Specs are (just in case):
C2D e6400
Asus P5N-E SLI
2x2GB 800MHz OCZ SLI
PowerColor X1950 Pro
WD 250GB
Windows XP 64 bit (has not been the most stable OS but never gave me connection issues)

RJ45 port supported by a Marvel Gigabit LAN controller, NVIDIA Ethernet Driver (nForce networking controller).

Thanks

 

[JackMDS]

Maybe this can Help, http://www.ezlan.net/debug.html

 

[deathsupport]

Thanks for the link Jack but nothing there helped. I tried resetting the IP stack and still nothing.
After some more tinkering and a few reboots it does manage to accept the IP address that I manually enter. However still doesn't ping the default gateway.
Might this be an issue with something under the Authentication tab? I don't remember the settings that were there before and maybe they were changed when I was messing with the connection.