Secunia Personal Software Inspector is now available in a updated version that is free for personnal use. The home page says

"The Secunia PSI is aFREE security tool designed to detectvulnerable andout-dated programs and plug-ins which expose your PC to attacks. Attacks exploiting vulnerable programs and plug-ins are rarely blocked by traditional anti-virus and are therefore increasingly "popular" among criminals.

The only solution to block these kind of attacks is to apply security updates, commonly referred to as patches. Patches are offered free-of-charge by most software vendors, however, finding all these patches is a tedious and time consuming task. Secunia PSI automates this and alerts you when your programs and plug-ins require updating to stay secure.

Download the Secunia PSI now and secure your PC today - free-of-charge."

I have used this for some time on my home PC and have found it to be very useful in identifying required updates. I use Google Chrome but I found that whenever a new version is issued, the old version is not de-installed. Secunia PSI helps me to locate them and get rid of them.