Ethernet connection problems...mobo? Need assistance.

Summary at the bottom for you "TLDR"ers.

Alright so I just picked up a 9600GT from my friend. Unfortunately, my PC is a bit old, so it lacked the necessary 6 pin power cable coming from the PSU to successfully power the 9600GT. I would've left it in anyways...but you'll find out why I took it out in about 30 seconds providing you reach the next paragraph in that amount of time. The only cables I could find for a 6 pin adapter needed two power sources, and I only saw one of those two available inside my case, so I set that aside. But I digress, since this is not the issue, however this is:

So I get the 9600GT. I go upstairs to put it in, had to take out my network card (wasn't in use, ethernet cable was in the motherboard port) to be able to fit the card since it needs two PCI-E slots. I fired it up with the 9600GT, worked fine other than the power issue. Had internet, nothing changed, etc. I shut it down. I took the card out to see what the actual cable I would need should look like, found the cable type...did some more random research, put the card back in an hour later. Fired it up, no internet. Restarted, no success, shut it down, sat dumbfounded for a few minutes, went to get the old network card that I took out. To be able to put it back in with enough space, I had to take out the 9600GT, so I did, and put my old @%$$bag video card in. Fired it up, installed the drivers I got off another computer, restarted, and I had the internet. I tried putting the cable back into the mobo port, lit up orange like it always does, but internet was still dead, "no ethernet cable plugged in".

So to summarize:

Ethernet cable was plugged into motherboard port. I took out my network card and old video card. I put a 9600GT in. Everything worked, had the internet. I took the 9600GT out, checked some cables, put them back in place. I put the 9600GT in. Internet failed. I took out the 9600GT. I put in the network card and old video card. I plugged the ethernet cable into the bad-boy network card. Internet worked. I tried the mobo, nada. I typed this post.