Steps for troubleshooting
Step 1 - Interview and Back Up Data
Step 2 - Establish Theory
Step 3 - Test Theory
Step 4 - Plan Fix and Resolve Problem
Step 5 - Verify and Prevent
Step 6 - Document
Multimeter
A devices used to take multiple electrical readings on electrical components
Power Supply Tester
A multimeter specifically designed to test PSU by having ports for PSUs