PC turns on. Screen stays black. Start here.
A safe, ordered checklist before you assume a component has failed.
Check outside the case first
Confirm monitor power and input selection. Reseat the display cable, try another port, and test a known-working cable or display if available. If a dedicated GPU is installed, its outputs are usually the intended display connection. Motherboard video outputs require supported integrated graphics.
Write down what the computer tells you
Record whether fans start, whether the system repeatedly restarts, and any motherboard diagnostic LEDs or codes. A DRAM or VGA light is a clue, not proof that the named part is defective. Interpret indicators only through the exact motherboard manual.
Respect the power boundary
Turn off and unplug the system before any internal inspection. Do not open the PSU, short pins, or mix modular power cables. Stop if you notice smoke, damaged cables, liquid or a burning smell. Ask a qualified technician when you are unsure.
Escalate with a useful record
Provide exact component models, the sequence of events, recent changes and checks already attempted. This saves repeating work and reduces guessed purchases. PC Doctor can save a checklist of the steps you completed.