G74SX Network Connectivity - Wired Components Aren't Receiving A Connection?

I recent bought an Asus G74SX-A1. While the machine runs like an absolute dream, it does seem to have a networking problem that I have been attempting to address for about a week. In my college dorm there is an ethernet port that carries an active internet connection. When my laptop is plugged into the port via ethernet, I receive no connection (well mostly no connection, every now and then I will connect for a split second allowing me to load my homepage, Google). This problem also exists on my dorm's WiFi. My LAN card is a RealTek BGE Family Controller (PCIe)

However, on my netbook (an Asus 1000HE, which I am typing this post on) everything is fine. I am quick to blame the retailer who sold me the G74SX seeing as they replaced the stock WiFi card with a Bigfoot Killer 1102 card, and my first assumption is that something was not installed properly during my laptop's assembly or that I simply messed up a driver update. I became quite frustrated with the whole situation and in order to find a quick solution I formatted the laptop back to factory defaults.

Something magical happened.For about a day and a half, my LAN card worked. I packed up my gear this weekend and headed back home, and at my parents' house my WiFi card worked wonderfully.I thought my networking woes were behind me, but this was not the case. When I returned to my dorm this afternoon, my LAN and WiFi cards began experiencing the same problems they experienced before the reformat. A third variable of some interest is that I brought my wireless router back to my dorm in order to utilize a less-crowded private WiFi spot and discovered that it worked fine and I was able to connect to the internet on my iPad using my router. This evening, however, my router decided to stop carrying an internet connection as well. I can connect to the router itself, but I cannot receive an internet connection, even on the netbook.

I have tried uninstalling/updating drivers for both the Bigfoot card and the RealTek card to no avail. My best hypothesis is that the problem lies in some setting that both the G74SX and the D-Link DIR-655 have in common, seeing as they are the only wired components that aren't receiving a connection.

Equipment: D-Link DIR-655, Asus G74SX, Asus EeePC 1000HE