In plain words
A PC that won't start is like a car that won't start: before changing the engine, you check there is fuel, the battery is charged and the key turns. The assistant follows the same order, from the simplest to the most complex, and never has you take a part out while a more obvious cause hasn't been ruled out.
How the assistant reasons
A PC's startup follows a chain where each link depends on the previous one. The assistant starts by identifying the last link that works, then tests the hypotheses from the most to the least likely:
| What you see | What already works | Where to look |
|---|---|---|
| No sign of life | Nothing | Power, power supply, power button |
| Fans but a black screen | Power supply | Monitor, memory, BIOS, graphics card |
| Turns on then cuts out | Power supply (partly) | Short circuit, overheating, unstable setting |
| Light or beeps | Motherboard | The component named by the light |
| Logo then error | Motherboard, processor, memory | Disk, boot order, Secure Boot |
| The system crashes | All the basic hardware | Drivers, updates, system files |
Before opening the case
Unplug the power cable before touching a component, touch a metal part of the case to discharge static electricity, and never open the power supply: its capacitors stay charged after it is unplugged.
If the assistant doesn't find it
If your case falls outside the paths offered, the guide PC won't start details the general method, and Windows 11 maintenance and repair covers system failures in depth. Without spare parts to test by elimination (power supply, memory module, graphics card), a repair shop has everything needed to isolate the faulty component.