Establish a Theory of Probable Causes

· First, create a list of the most common reason why the error would occur

· Even though customer think that there is major problem, start the obvious issues before moving to more complex diagnose

· As outline here:

• Device is powered off.

• Power switch for an outlet is turned off.

• Surge protector is turned off.

• Loose external cable connections.

• Non-bootable disk in the designated boot drive.

• Incorrect boot order in the BIOS setup.

· List the easiest or most obvious causes at the top and more complex causes at the bottom

· If necessary, conduct internal (logs, journal) or external (internet) research based on the symptoms

· Next, test each of these causes in the next step of troubleshooting process