Belarc Advisor builds a detailed profile of your installed software and hardware, network inventory, missing Microsoft hotfixes, anti-virus status, security benchmarks, and displays the results in your Web browser. Video walkthrough available.
While there are a lot of free choices in system information tools, Belarc has the advantage of being around the longest.
Its a tool found in most techs toolboxes.
Editor's Note: You may see Belarc bumped as new, but it's still the same version you have. This is because the database has been updated. If you already have Belarc installed directly update your database in the program.