Yeah to make things simple, every computer when connected to the
internet, is assigned an IP address. Some IP address are Static,
while others are Dynamic. The ones which are static never change. U
can switch off the computer, unplug, do whatever, but they won't
change unless request is sent to the ISP (internet service
provider). On the other hand for Dynamic IP addresses, they can be
easily changed by just unplugging the modem from the cable socket
or adsl socket and reconnecting after sometime (10-15mins)
Thats the simple version :p