You can find the IP address of a computer by following this steps:
1. Go to Start ->Run, type cmd and press Enter.
2.Type ipconfig/all and press Enter.
3. You will receive a lot of information about your network settings including the IP address.
The IP address is an unique generated number in a network which identifies the computers in the respective network. The IP will be different from network to network. If you move to another ISP your IP will be different.