PC Won't Boot? No POST Troubleshooting Guide with Beep Codes | Repair Guide | Nexus Parts Online

Your desktop PC will not boot. You press the power button and either nothing happens at all, the fans spin briefly then stop, or the system powers on but never reaches the BIOS screen. This is called a no-POST condition , the computer fails its Power-On Self-Test before ever loading an operating system. The causes range from a simple loose cable to a dead power supply or failed motherboard, and the only reliable way to find the culprit is systematic elimination. This guide walks you through a structured diagnostic sequence that starts with the most common and easiest-to-fix causes and works toward the least common and most expensive. Along the way, you will learn to interpret beep codes, read debug LEDs, perform the PSU paperclip test, and execute a minimum boot configuration that isolates exactly which component is preventing POST. The process applies to any standard ATX or micro-ATX desktop build regardless of brand , whether you assembled it yourself or bought a prebuilt from Dell, HP, Lenovo, or any other manufacturer. Fresh, structured diagnosis beats scrolling through a 2012 forum thread where half the replies say "just RMA everything." When you find the failed component, you can source tested replacements from Nexus Parts Online and get back to a working system with confidence.