PC will not restart (red led light) but is running fine from cold boot

Troubleshooting a PC That Won’t Restart Properly: Resolving Red LED Indicators and Boot Issues

Many PC enthusiasts and daily users encounter perplexing hardware behaviors that disrupt their workflow, especially during routine operations such as restarting the system. A common yet often frustrating scenario involves a PC that boots flawlessly from a cold start but exhibits issues when attempting to restart. This article explores such a situation, focusing on diagnosing and resolving the problem effectively.

The Scenario: Perfect Cold Boot, Problematic Restart

A user reported experiencing a peculiar issue: their PC functions perfectly when powered off and then turned on (cold boot); however, when they try to restart the system—either via Windows’ restart option or during a reset process—the system fails to reboot properly. Instead, a red LED on the motherboard illuminates, and the display remains blank, with no access to BIOS or any on-screen output.

Key observations include:
– Successful cold boot ensuring the system runs without issues.
– Failure to restart results in a red LED indicator on the motherboard.
– No display output during restart attempts.
– BIOS access remains unavailable during restart.
– The issue persists despite BIOS being updated to the latest version.

Hardware Details

The setup in question comprises:

Motherboard: Asus ROG Strix B650E-I
Processor: AMD Ryzen 9 9950X3D
Graphics: Integrated graphics
Power Supply: Corsair SFF 1000W
Memory: 48GB Corsair DDR5 5600MHz

Initial Troubleshooting Steps

Given the symptoms, several common troubleshooting steps can help narrow down the root cause:

Check for BIOS Compatibility & Updates:
The BIOS is already updated to the latest version, which addresses compatibility issues with newer CPUs and hardware features.
Clear CMOS:
Resetting BIOS settings to default can resolve misconfigurations. Since it has been attempted, further BIOS-specific options like disabling certain features (e.g., Fast Boot, CSM) may be considered.
Inspect Hardware Connections:
Ensure all power connectors (24-pin motherboard, 8-pin CPU power) are securely attached. Verify RAM modules are seated properly.
Test with Minimal Hardware Configuration:
Remove non-essential components and peripherals, leaving only the CPU, one RAM module, and integrated graphics.