I missed the part about him wanting to block access to the sites. I was only referring to stopping the spyware/malware threat.

Porn sites are no more likely to have malware than a lot of other sites. Most anti-virus software does a good job of protecting you against such threats as long as they are regularly updated.

Chances are any attempt to use technical means to prevent access to porn will fail. Your 12 YO kid has more time to learn how to get around those means, then you have to learn how to block him.

I think you need to look at this the same way you would look at him bringing home a "men's" magazine. You can't prevent that either.

Are you willing to subject him to regular humiliating and degrading searches (electronic or physical) to prevent him accessing these kind of materials? If so, feel free to proceed. But know up front you will almost certainly fail, and you need to figure out what you are going to do when you find out just how bad you have failed.

Here is a freebie that works OK to block porn and other categories of websites:

http://www1.k9webprotection.com/

Just how does such a piece of software prevent accessing porn, when it is trivial to bypass it?

Think booting from a USB or other drive, so this kind of software never gets a chance to even startup.

And what is to prevent a kid from spending $79 on a netbook that you don't even know about?

I can't tell if you want this person to stop visiting porn sites or not: if you don't want porn sites visited from your PC, create user accounts for each person who uses it, and require passwords to logon - don't leave an account open without a password requirement. If this is your PC, you control who logs on: if its a common PC intended for random logons, set some new rules for use. Either you want the porn visits or not, just decide. fwiw if you don't object to the visits, I think a $79 netbook or a $249 desktop for your little diddler would go a long way towards addressing this issue: let the person mess up their own PC, not one used by others.

Thanks for all the suggestions guys and gals. We are going to go with and easiest/stricter approach. NO unsupervised pc time. ie, pc password changed and will stay locked unless someone is home. The pc in ? is already in the living room so it being unlocked only during hours of family occupation will solve the problem right quick.

And to touch on what a few of you had said, previously there was family trust so only 1 master account for everyone. I have to set up the computers in the house and am by know means a master at it. I dont feel that one bad egg should make me have to set up user accounts for each person (I then have to go in and help each person set up their individual settings, etc) So the bag egg just loses the privelage. Had to step back to think about it, sometimes the easiest solution just works.

Off topic:

Where can I get a decent netbook for $79 that you all keep talking about?

Long gone are the days when a photograph of the Duchess of Arbroath without a hat on was enough to maintain not only a stiff upper lip, I'm afraid.

Great advice. On my 'serious work' PC I have gone that way. Takes some getting used to but once set up it is pretty much bulletproof and so reliable and trouble-free, compared to Windows, that it is scary.

If rally must use Windows, my online beater PC is running Windows, I recommend you start by switching browsers to Mozilla Foxfire. That alone stops a lot of problems. Fortify Foxfire with Adblock Plus, Better Privacy, and Request Policy as ad-ons for added security. Also set Firefox up to clear all, cookies, cashes, history when shut down.

Of course the PC needs protection from a firewall, I used Zone Alarm but the free version has become nerfed to the point that it is not much better than the firewall included with Windows. Comodo firewall is both free and highly rated. It does more than most.

A good anti-virus program is vital. A decent free one is Avast Anti-virus but there are others. If you are wiling to invest a little money you can get better.

Spybot Search & Destroy and SpywareBlaster are Anti-spyware/malware programs that are well rated and free. When checking them out be careful of the spelling. There are programs that sound-a lot like Spybot Search & Destroy that are malware.

As I understand it porn sites are not the greatest source of viruses and bugs. Porn site owners have a pretty powerful incentive to keep their sites free of viruses and malware. Any site that gets a reputation for being infested tends to get blacklisted and loses traffic. It isn't good for business.

Many viruses and nasties get spread through e-mail and downloads. Particularly small downloaded Flash games and widgets that claim to improve PC performance, check for bug, and ironically, scan for viruses.

Do NOT take any recommendation at face value. Not even my own. Check any recommendations against sources you consider reputable. CNET and, other online magazines with well known authors are generally reliable. You may not like the programs they like but they are not likely to steer you into a trap. Generally a Google search of any program and a bit of digging down will make it clear which sources are scams and which ones gold.

If your intent is simply to protect your computer from damage, but still allow Mr. Porn to view his websites, boot from a Linux LiveCD and do not mount any harddrive partitions.

If you want to block Mr. Porn and turn him into Mr. Family, I hate to say it, but nothing much is going to work for you. Unless Mr. Porm is exceedingly computer-dumb and you are exceedingly computer-smart. It would be trivial to bypass anything you might set up. Mr. Porn could simply choose to boot with that same Linux LiveCD mentioned above and go surfing away, no matter what you set up on the computers harddrive.

If you want to allow Mr. Porn to view his websites, and you want to protect your computer, and you want it to be running Windows - sorry Charlie, no way on that one. You can add a ton of software, causing all kinds of conflicts and slowdowns, and end up not much better than you were in the fist place.