Every review that I've found on your motherboard the MSI KT4 sais that the motherboard has a built in network adapter (possibly a really fast gigabyte ethernet one)
You could further disable this device in the device manager. Right click MY COMPUTER - MANAGE - choose DEVICE MANAGER on the left side find NETWORK ADAPTERS, and Disable the device from there.
Exactly how long does it take for your PC to start up? What screen does it sit at for the longest?
