Changing DNS servers.
Direct Connection to the modem Via Ethernet.
1) Open Network Conections, this can be found in the control panel, and sometimes from the start menu itself.
http://www.samputer.com/CF/networkconnections.JPG
2) Right Click the connection you are using (Will most likely be called Local Area Connection 1)
http://www.samputer.com/CF/rightclick.JPG
3) Select Properties
4) Select "Internet Protocol (TCP/IP)"
http://www.samputer.com/CF/tcpip.JPG
5) Click Properties
6) In the new window that appears, you may need to select "Use the following DNS server addresses"
http://www.samputer.co.uk/CF/dns.JPG
7) Fill in the fields with the required DNS servers.
8) For the freeserve ones it will look like this
http://www.samputer.co.uk/CF/done.JPG
9) Then Click Ok
10) Click Ok again
11) Next you need to make sure the settings take place, you can either reboot or...
12) Right click on your connection (remember which one we just edited) and select "disable", wait a few seconds and select "enable".
http://www.samputer.co.uk/CF/enable.JPG
13) You should now be all set
Hope this helps.
Copy & Paste links i'm afraid, sorry