[Skunkworks] Internet connection issues

Hi guys, I recently upgraded my PC by changing the motherboard, and other parts, and since then, I have been having issues with my connection. I have spoken with someone from my ISP and she said the problem could be on my side. Whenever I dial up, it's an iBurst connection, I get connected, but the link only stays up for a short time then becomes so slow. If I disconnect and reconnect, it fails to resolve DNS entries, so I reboot and the connection is back again, only for the link to become slow again after a few minutes. So I've been wondering whether it could be my NIC... coz apparently, I'm the only one on iBurst having that issue, according to the person I spoke with from the ISP. Anyone know what my problem could be? Thanks, Me.