Or, how to get your computer to work on the local network
DHCP (Dynamic Host Configuration Protocol) is used to automatically provide each computer on the network and few pieces of information that are used to access the network and the internet. In olden times we used to enter this information on each computer by hand, but now, in places like schools and businesses which can have 10's or 100's of computers this isn't effective anymore, so the DHCP protocol allows each machine to get this information from a server, where it can be set once and used by all the computers automatically.
Think of DHCP as the front desk in a large hotel. When you check in to the hotel, you are given a room key (your IP address) and information about how to call for room service (your DNS servers).
Add a section here on how to set machines for automatic DHCP activity.
You can use this technique to have your PC or Mac to try its DHCP request again by one of the following means:
Setting particular hosts for a Windows machine:
 From http://homepage.ntlworld.com/robin.d.h.walker/cmtips.html.