The Secunia Personal Software Inspector  is an invaluable tool for you to use when assessing the security patch state of software installed on your system. It constantly monitors your system for insecure software installations, notifies you when an insecure application is installed, and even provides you with detailed instructions for updating the application when available
It is NOT the purpose of the Secunia PSI to detect whether your system has already been compromised or if local changes, settings, or missing requirements could cause the Secunia PSI to report incorrect results. The Secunia PSI relies on the meta-data of executables and library files.
The Secunia PSI works by examining files on your computer (primarily .exe, .dll, and .ocx files). These files contain non-specific meta information provided by the software vendor only. This data is the same for all users, and originates from the installed programs on your computer – never from their configuration.
The Secunia PSI does NOT conduct an integrity check of the individual files, rather, it checks whether a specific program is vulnerable according to the reported version numbers and not whether the files have been compromised or replaced by other users or programs.
Free download  for Private/Home Users available.