Not a perfect solution but it will help.

Use Linux and run it off a Live CD or DVD.

I currently use Ubuntu but I may change to Mint and I don't even have a Hard Drive plugged in, so there is no way for anyone including the Gov, to permanently install anything, including applications or illegal content on my system, also there is no record of Internet activity kept on my system, once the system is powered down everything disappears.

You can also fully encrypt your entire system so even if a scum sucker did manage to load illegal content to your system, they would have to break the encryption before they could use what they did to persecute you.

You can also use a VPN like

http://www.bestvpn.com/blog/3407/expressvpn-review/

http://www.bestvpn.com/blog/3711/private-internet-access-review/

along with a fully encrypted system.

but a VPN can not be used at the same time as a Live CD/DVD at least without making a custom Live CD/DVD.

There are no perfect solutions except to run your computer over with a Cat D9.