who are you trying to hide it from - the sites you are visiting? That's not governed by the PC - you have a private address anyways, it's the public facing IP outside your router that they see. Something like a proxy service is what you're looking for.
I use a proxy already, just looking to improve my security and keep from getting virus's and worms, and the government can kiss my butt as well. I am not doing anything illegal. I just look for every way to keep from having to work on my pc because of others.
hiding your IP won't stop viruses. You could run inside a VM for browsing, then delete the VM and create a new one if it gets infected, or dual boot into Linux for browsing. OR simpler stuff, like don't run as an admin under windows, run as a standard user, keep up to date, etc.
most virus's and worms are caused by the end user downloading and running what they shouldn't. The only way to stop that is to not allow those users to have internet access.
if you want to "hide" your IP, the only way is to bounce your data off of another server aka proxy.
You can't do it any other way because an IP is REQUIRED for data to get back to you, unless you believe in fairies, unicorns, and magical routing.
On the other hand, trying to hide from the government by using a proxy means you're passing all your data through someone you don't know. They could easily be spying on your data and it is the perfect way to man-in-the-middle a connection. This means they could fake an SSL session. Since the proxy would be seeing all the data, it could eves drop on an SSL/HTTPS connection and you'd never know.
Pay 5-10 dollars a month for a full vpn like connection through a hosting company. I've tried Ipredator, which is hosted in sweden. Its like 18 dollars for 3 months, and to anything you access outside of your own network the traffic will go through a server in sweden, and it will look to the destination like that is where it originated from. This doesnt stop viruses. not downloading random *** from the internet will do that though.