Patch My PC is an easy-to-use tool which can quickly check your PC for outdated software.
Just launch the program, and it will check your installations of Adobe Reader, Flash, Java, Firefox, Quicktime and Acrobat (if present), highlighting any which aren't the very latest version. If you spot any problems, just click "Run Updates" and Patch My PC will download and install any required updates for you.
The program can also check the following packages for updates: Microsoft Security Essentials, Google Chrome, CCleaner Slim, Defraggler, ImgBurn, VLC Player, File Zilla, WinRar, Pidgin, itunes, Dropbox, Safari, Google Earth, Spybot Search & Destroy, KeePass, Picasa, Malwarebytes, Speccy and Shockwave.
And just for completeness, Patch My PC will also display whatever Windows updates might be available for your system. Which could be useful, even if you have the essentials installed automatically, as it displays details of the optional updates as well.