How can I hide or change my IP address?

You are referring to IP Masquerade. Check this link for more info on how to. http://www.kobore.net/soft/pipmasq/ Good luck.

You can use proxy servers and software... ( read: http://stayinvisible.com/ ) The best way is to use VPN ( Virtual Private Network ) like: https://www.steganos.com/us/products/home-office/internet-anonym-vpn/overview/ Or metropipe vpn... or for free use: http://your-freedom.net

Changing an internal IP address shouldn't be a problem at all, though it would be very useful. Hiding an outside IP address is not possible though, as you need one to have internet presence. Changing an outside IP address is also problematic, as most of the time, your ISP controls it. The most you can do to surf anonymously (which I assume this question is based on), is using an anonymiser like this: http://www.anonymizer.com/consumer/products/prod_matrix/ But as you can see, good service/products mean there's a price tag attached to it

depends if your dymanic or static. If you have a static address you will have to call your ISP. If it's dynamic you can click start, run and type cmd. Then you can type ipconfig /renew to renew your address.

You can use Tor http://www.torproject.org/

You can't. Your Ip address must be known to what ever system you are trying to connect to... It's just part of the protocol. If the system you are connecting to doesn't know your IP address, it has no way of "returning" the information packets to you. Your actual "public-side" IP address is controlled by your ISP. Sometimes turning off your modem (cable or DSL) for a few hours or a few days will give you a new IP address, sometimes it doesn't, it all depends on your ISP's equiment and setup. (If you were doing something illegal, your ISP logs all the information of who has what IP address at any given time, so changing it won't help.) As to how to "hide", using a "public proxy server" can provide some protection, for some stuff, but won't work for everything