Windows symptoms: blue screen (BSOD), degraded performance, boot problems, frequent shutdowns, services not starting, application crashes, low memory warnings, USB controller resource warnings, system instability, no OS found, slow profile load, time drift

Troubleshooting starts with recognizing a symptom and knowing what it usually points to. The exam describes what a user sees and asks for the most likely cause or the best next step, so you need a mental map from each symptom to its common causes. Before jumping to fixes, ask three questions every time: what changed recently, does it affect one user or many, and is it more likely hardware or software? These questions narrow the list quickly and are the start of the CompTIA troubleshooting methodology.