l0stat is a tool that uses L0phtcrack or LC3 results in order to generate a set of statistics that provide a global security view of the NT password database 
It provides statistical info about all user or computer accounts in terms of:
- Basic Analysis: gives a global view of strength of password account.
- Position Analysis: gives a detailed view of patterns of password contents.
Statistics point out that today even young kids often become "hackers" after reading a few docs published on the Internet 
If you don't want to be responsible for your kids buying goods on-line with stolen credit cards, you need a program like KGB Keylogger that logs all keyboard activities and applications running. The program can send you reports via e-mail. You will have access to all e-mail written by your kids and all their passwords.
I wanted a software for blocking unwanted users and I found WinGuard Pro. I installed the free edition, although there is a professional (premium) edition available on the publisher’s website. In the free version you are not allowed to add protection to any program beside those that are predefined, including Mozilla, MSN Messenger and Windows Media Player, Control Panel, Date and Time and the Run command. You can also protect the whole system by simply selecting a checkbox. 
Activity Keylogger records all keystrokes typed, chat conversations, screen, websites visited and system clipboard 
During monitoring sessions Activity Keylogger can be customized to be completely invisible and cannot be seen in the taskbar, task manager and system tray.
Activity Keylogger exports log reports to HTML files and emails to you automatically, so you can conveniently read the reports in a browser such as Internet Explorer.
Scans your computer for malicious software (Malware), including Trojan Horses, Dialers, Worms, Spyware, Adware and more 
a-squared Free is specialized in finding and removing them securely. The disk scan checks all files on your system disks for Malware. The scanner scans for Spyware Traces. Currently more than 1.2 million different types of Malware may be detected and removed. Free daily online updates provides the best protection.
Steganography literally means ‘covered writing’ and it seems that it became already a science. It’s the science of hiding the existence of secret messages. The most common methods were invisible ink, microdot, digital signature, covert channel and spread spectrum communication. 
From the point of view of this software, the steganography works by replacing bits of useless or unused data in regular files such as graphics, sound, text, HTML, or even floppy disks, with bits of different, invisible information.
An open source command line anti-virus scanner for Windows that is fast and powerful and can easily be integrated with server applications for use in a mail server or proxy server 
It can also be used to scan individual files or folders when necessary.
Includes a high speed scanning daemon, completely free and unlimited definition updates, and full documentation.
Anti-Spy 
Info is your security and personal privacy tool that detects and removes spyware, trojans, keyloggers and adware. It complements your firewall and anti-virus software. Anti-Spy.Info tells you every hidden function of all dynamic link library, system task and threat currently active on your computer. Anti-Spy.Info stops keylogger or other hacker tools and protects from trojans that stealthy add an autostart key.
IMMonitor Yahoo Messenger Spy allow you to monitor, block or record Yahoo Messenger conversations remotely, If your kids (or spouse!) are spending too much time chatting via Yahoo Messenger, or you suspect they're engaged in dangerous conversations, IMMonitor Yahoo Messenger Spy is a very simple way to find out and stop it 
You can save all intercepted messages to HTML files for later processing.
Protector Plus 2008 is an Antivirus software designed for Windows Desktops and Servers 
Protector Plus is known for its compact size with an efficient scan engine. It includes powerful features like Real-time scan, Email scan, Automated virus signature update and Automated virus sample submission. The interface is attractive and easy to use. It works on all flavors of Windows. Download this 30 day evaluation copy to try it free of cost.