Yarr, you're all amateurs!!
Step by step:
1. Open a command prompt by going to 'Run' and typing 'cmd' - press Enter.
2. In the new window, type: ipconfig /release ... and then press Enter.
3. Go to the Control Panel, and then onto 'Network and Internet Connections'. Then click 'Network Connections'.
4. Right click on your broadband connection, and go to 'Properties'.
5. In the new Properties window, scroll down to 'Internet Protocol TCP/IP', and click on it, and then click 'Properties'.
6. Click 'Use the following
IP address' and enter something like 192.168.123.1, and then press 'Tab' to go down to 'Subnet mask' (and it'll automatically fill it in with '255.255.255.0' for you.
7. Press 'OK'.
8. When back to the Properties window, select 'Internet Protocol TCP/IP' again and click 'Properties'.
9. Select 'Obtain an IP address automatically' and 'Obtain DNS server address automatically'.
10. Click OK, then OK in the Properties window.
And there you have it, a new IP address all to yourself. 
(I'm a genius, you know? 
)