open a cmd box by running it as admin.
Type ipconfig/ release
When the prompt comes back type ipconfig/ renew
If you are running of a router or a dhcp server you will 99.99% of the time get the same IP address without first removing your entry from the server/router.
If you hard set your IP address, just change the last number to something else not being used. How to do this.....Google is your friend.