RipCurrent's PC Diagnostic Pro

It doesn't so much diagnose PC issues as use a process of elimination to help uncover them, but this free program could be a useful tool for the novice user.

The user interface is kept very simple and the large "Click Here to Begin" button makes it obvious how you get started. There's no Help file, but the radio button operation is very easy to understand. The program begins with the most obvious issues, such as virus protection. From there, depending on your selections, it offers advice on what kinds of maintenance you should perform. It even offers links to programs, like a Registry cleaner, that might help you fix the problem.

A lot of the advice RipCurrent's PC Diagnostic Pro brings is probably common knowledge to the more experienced users. For the novice user, although it might not specifically diagnose issues, it can help troubleshoot them at no cost.