Computer Turns On but No Display
The computer powers on — lights, fans, sometimes drive activity — but the monitor shows no signal, stays black, or displays "no signal."
Quick answer: This is usually a graphics card, RAM seating, or monitor connection issue rather than the computer being fundamentally broken — it's a different fault to the computer not turning on at all. Check the monitor cable and try a different video port before assuming the worst.
Likely causes
- A loose or faulty monitor cable, or the cable plugged into the wrong port (motherboard vs graphics card)
- RAM that's become loose or needs reseating
- A failed or failing graphics card
- The monitor itself set to the wrong input source
What you can safely check yourself
- Check the monitor is on the correct input source (HDMI 1 vs HDMI 2, DisplayPort, etc.)
- Try a different cable and a different port on the computer
- If the computer has both a graphics card and onboard graphics, make sure the monitor is plugged into the right one
- Listen for beep codes on startup, which can indicate a specific hardware fault
When it needs a proper look
If the monitor is confirmed working (tested with another device) and different cables and ports don't help, the fault is internal and needs proper diagnosis.