Question: I recently reinstalled the OS (Windows XP Home) on a friend's heavily spyware/adware infected machine. It appears as though his kids (7 and 11 years I believe) were visiting sites that offered downloads for search bars, screensavers, and "cute" cartoony animations that anyone with safety in mind would never download.

Some of the concerns I noted on the machine were:

* The main account was Administrator
* Expired anti-virus software
* Lack of Windows updates
* Multiple firewalls installed

Basically, I'm looking for a guide for non tech-savvy users that would help them avoid getting infected again.

Answer: 
Ask your friend to browse/ do his work in a virtual machine (VM), and prepare a backup image so that whenever that VM is infected, you can always delete it and restore from the backup image.

Or, maybe you can use [Sanboxie](http://www.sandboxie.com/) to [isolate the browsing and BitTorrent software](http://www.sandboxie.com/index.php?SandboxMenu#create).
My issue is about having the kids grow up learning. SteadyState styled solutions, which so far sound like the most attractive, will either A) be a limitation to what the kids can learn, or B) will be worked around at some point by the kids. Either way, you're limiting the kids' ability to be become good computer users.

I'd recommend that you basically setup a state rollback that is voluntary, I don't know if SteadyState offers this choice. This is something you'd do from a safe start. You then teach the kids to do that, and explain to them why they need to, what they lose when they do it, and how to avoid having to do it. Additionally if it ever happens that your friend chooses to rollback, he should use the opportunity to show the kids what's wrong with the machine, theorize on why it happened, and have one of them pull the trigger on the rollback, while possibly letting them keep some of the misplaced files and such that invariably they will have and want to keep.