The only way I know on how to contain the 'situation' is something called "PARENTAL CONTROL". Windows 7/Vista has in-build parental control features that you can set up to control children from accessing adult sites, downloading files, or allow/block specific programs. Also there are many 3rd party software suites (such as antivirus suits) that have their own parental control programs. All in all you need to experiment and look for something that suit your needs. A google search on parental control will bring up TONS of information on the subject. The best way to start, in my opinion, is the Windows' own parental control system, and there is how to activate it: http://windows.microsoft.com/en-US/windows-vista/Set-up-Parental-Controls. Google has also a few parental control programs that integrate into the google search bar, blocking 'explicit' searches.

You will not be able to tell if Firefox was used in private browsing mode. When in that mode Firefox does not store any details about web browsing.

One option you can use is to install a free parental control program such as K9 Web Protection - http://www1.k9webprotection.com/ - That program can be used to block access to sites based on categories that you choose. It will work with all browsers and does not matter if they are in private browsing mode or not.

@ foxniko & TonyE ~ Thank you for your help! A while back, I did purchase a filter called Net Nanny... I selected "porn sites" to be excluded. Unfortunately, there were many times when he tried to pull up a site that was totally innocent of porn content! It was very frustrating because I would have to log into Net Nanny in order to "allow" a website! That worked great when I was in the house! However, there were times when I wasn't even here! Do you know if the above-mentioned "parental-controls" will disallow him from accessing "legitimate" websites like Net Nanny did? Yes! I finally disabled Net Nanny because I was constantly having to "allow" legitimate sites for him to use! Lastly, why doesn't Mozilla Firefox simply set up "Private Browsing" so that someone like myself can simply "monitor" (Not Control!) Private Browsing's use on a computer? Should I contact Mozilla Firefox directly to suggest that "option"? I have heard about eBlaster keyloggers. Do y'all know anything about how those work? Are they safe to use?

The whole idea of private browsing is that it records no details. Mozilla will not change it so that it can be monitored. If they did there will cause a lot of complaints from people who will rightly say that the private browsing feature is no longer private.

I have never used any keyloggers so can not comment on them.

Note that removing or disabling "Private Browsing" will not make it impossible to delete private data like visited websites (history) or cache or cookies.
There are a lot of ways to clear such data, either via Delete browsing, search and download history on Firefox or directly by deleting the History in the Library or sidebar.
Private Browsing makes it easier because all data is kept in memory and nothing is saved to disk, so nothing needs to be removed.

If you want to see which sites have been visited then you should look at others means outside Firefox like a router or firewall with a password protected logging feature that can't be bypassed or a program like Wireshark.

• Wireshark: http://www.wireshark.org/download.html

See also http://kb.mozillazine.org/Parental_controls