On the subject of computers and security issues, the tendency is to think in terms of protection such as anti-virus and firewalls. Keeping Windows updated against vulnerabilities is another obvious measure, but rarely do we mull over the prospect of what holes might be opened by the various pieces of software installed on our PC.

Enter stage left the Personal Software Inspector (PSI for short), with a flourish of its cloak and a knowing glint in its eye. This detective program from Secunia is designed to supplement your existing anti-virus protection, examining each piece of software on your machine and reporting back with details on those that are missing security updates.

After installation, PSI performs its initial scan, which takes a couple of minutes (or longer if there's an absolute ton of stuff on your PC). The resulting vulnerabilities are then displayed, or at any rate, some of them are. This is because the program initially runs in simple interface mode, with an "easy patch" feature that's designed to provide instant point and click fixes for major problems.

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However, there will probably be issues requiring slightly more involved patching processes, and these are only revealed when you switch to the advanced mode. When we ran a scan, the basic mode picked up a couple of problems with Windows Vista and Media Centre (easily solved by following PSI's link to the Windows update site). Upon selecting the advanced interface, several further necessary fixes were revealed, pertaining to our Flash player and Adobe Reader installations.

In truth, running the advanced patch system is a far from complex affair; it just requires a bit more care. For example, with Adobe Reader, PSI pointed us to the latest version (8.1.6), but the diagnostic text that accompanied the patching instructions stated that we should only install this if we'd already updated to 8.1.5. This wasn't the case, and we had to open Reader and update it three times (from 8.0.0) before we could use the link PSI provided. The lesson is to read and follow the instructions Secunia presents carefully.

The Flash player update was a touch more convoluted, as even after we'd patched it to the latest version using PSI, it was still reported as a security threat. A quick visit to the community forums, via a handy link built into the interface, revealed the solution to this apparently common dilemma (completely uninstalling Flash and reinstalling from scratch, rather than updating). The forum is certainly a handy resource for any application that does prove problematic.

Secunia has also included a web browser monitor that looks for holes in the common browsers. It pulled up several in both Internet Explorer and Firefox, although no patches were currently available for these, so there wasn't much PSI could do apart from issuing a detailed security advisory to let us know exactly how the exploit in question worked.

We did experience one crash while using the program, in the middle of a scan, but otherwise it was stable. If you leave PSI running in the background, it will continue to monitor your system and provide warnings on new vulnerabilities that crop up in both existing and freshly installed software.

The Personal Software Inspector is a useful second line security utility, particularly given its freeware status. It runs smoothly, by and large, and if you encounter any slight hitches as we did, the Secunia forums prove a helpful resource.