You can release and renew your IP address, but you'll most likely pull the same one.

To release and renew the IP using the GUI

Go to Start, Run, and type winipcfg ... click OK

Now select your NIC and release and renew your IP.

Anyway, rb6teg is right....sometimes....the IP addresses are DHCP, but unless the DHCP server sees a need to reassign the IP...you'll get the same one. The best way to do it is to swap out the NIC, but you're fux0r if your ISP requires MAC registration.