My PC won’t start (“no signal” on screen but fans and lights turn on)

Understanding and Troubleshooting a “No Signal” PC Startup Issue: A Step-by-Step Guide

Experiencing startup problems with your personal computer can be frustrating, especially when the screen displays a “no signal” message despite the fans and lights turning on. This guide aims to provide a clear, professional overview of common causes and troubleshooting steps for such an issue, based on a real-world user experience.

Case Overview

A user from France reported a sudden inability of their PC to start properly. The symptoms included fans starting to operate, then stopping and running at an unusual rhythm, with no display output. The computer was built in 2017 and configurations included:

Tower: Cooler Master N200
Power Supply: Corsair CX430 Bronze, 430W
Storage: Crucial MX300 SSD (275GB) with Windows 10
Additional HDD: Seagate BarraCuda 1TB
Processor: Intel Core i5 7400
Motherboard: MSI B250M PRO-VDH
Graphics Card: MSI GeForce GTX 1060 6GT OC V1 (6GB)
RAM: 64GB

The user mentioned that the PC was functioning normally the previous day, and the recent location change during a heatwave in southern France may have contributed to the issue.

Potential Causes and Troubleshooting Steps

Check External Connections and Display Setup
Ensure that the monitor is powered on and correctly connected to the graphics output.
Test with a different cable or monitor to rule out display issues.
Confirm that the input source on the monitor is correctly set.
Inspect Power and Hardware Connections
Turn off the PC and unplug it from the power source.
Open the case and verify all internal connections:
- Power cables to the motherboard and graphics card.
- Data and power connections to storage devices.
Reseat components where possible, especially the RAM and graphics card.
Diagnose Graphics Card and Output
Since the system has a dedicated GPU, try:
- Reseating the GPU.
- Connecting the monitor directly to the motherboard’s integrated video output (if available), bypassing the GPU.
Note: The Intel Core i5 7400 does not have integrated graphics; verify if the motherboard supports integrated video, or test with a different GPU if available.
Listen for Beeps or Observe Indicator Lights