Every few months I run "Belarc Advisors" and then make a printout - it tells you everything that is on your computer - programs, operating systems, printers. check it out!.
http://www.download.com/Belarc-Advisor/3000-2094_4-10716621.html
The Belarc Advisor builds a detailed profile of your installed software and hardware, missing Microsoft hotfixes, anti-virus status, CIS (Center for Internet Security) benchmarks, and displays the results in your Web browser. All of your PC profile information is kept private on your PC and is not sent to any web server.
Hiring a professional computer-security consultant is out of reach for most home PC users, but Belarc Advisor can fill part of that gap.
The app analyzes a machine's weak points, looking at elements such as whether antivirus software is up to date, or whether all the security flaws in Windows have been patched. It uses the Center for Internet Security (CIS) benchmark test to give the computer a score showing its overall security level, and produces a report that can be viewed in a Web browser.
Not only does it analyze software and operating system components and tell you where problems are, but in its comprehensive report it tells you what your computer's physical components are: not just how much RAM you have, for example, but what kind of RAM and which slots are occupied.
This program doesn't fix the problems itself, but gives clear advice on how to address each issue. This download is free for personal use; we recommend it to home users as a first step in securing their home systems, or for those considering a hardware upgrade who want to see what's in their current system.