Performing Differential Diagnosis
To identify a problem and pinpoint a resolution, it is often useful to employ a technique known as differential diagnosis. This means examining the behavior of the computer system, matching that behavior with possible problems, and filtering out the most likely causes.
If someone complains of a computer that freezes every time a certain application is launched, then that application is a likely starting point for investigation. At the same time, the real problem might lie in a new video driver or a corrupted data file in use by the program. As with hardware troubleshooting, listening carefully, using a step-by-step process to eliminate other potential causes, good documentation and experience are valuable tools.
In developing a differential diagnosis, you contrast possible causes and work to eliminate all but one. You then validate your assumption by seeing if there is a demonstrable problem with that component. If there is, and fixing it makes the underlying problem disappear, then you have empirical proof that your diagnosis was correct. If not, you must proceed with the process of elimination.