Hard wired system keeps dropping connection in new network

Just put together a new home network. Using mostly new equipment for everything. The wireless router is a D-Link DIR-825. The wireless network is working well for the most part, but one of my notebooks is having sporadic issues. More concerning is that I have one ethernet cable connected tot the router which is plugged into port 1 of a 16 port gigabit switch. From that switch I have one port connected to a desktop system, one port connected to a docking station for a notebook, one prt connected to a network printer and one port connected to a VOIP phone. Most everything seems to be working fine except that the desktop system running Windows 7 Ultimate, keeps dropping the internet connection. It will function when I log in, but then at some point I will click on a web link and it will time out. I have to wait for minute or 2 before it re-establishes connection. Not sure what could be causing this. I want to connect my newly built Windows home server, but I want to make sure it has a constant cnnection. Any suggestions.

I did try another port on the switch and another port directly on the router and the connection keeps dropping. I have to assume it's something with the embedded NIC on the new system. I do not know why it would be dropping the connection. Anyone know how to diagnose a bad NIC, or could it be a setting?

Thanks for the advice. I forgot to update the thread, but I updated the firmware on the router and that seemed to fix the issue. In the list of fixes the firmware corrected, there was an entry pertaining to IPV6.

Thanks for the help.