You press the power button and nothing happens. Or the fans spin, the lights glow, and the screen stays black. Before you price a new motherboard, run the checks on this page in this order. In most homes and small offices the killer turns out to be something small, loose or switched off — and the first five minutes tell you which family your problem belongs to.
A computer that will not start feels like a dead computer, but will not start is really four different problems wearing the same coat: no power at all, power but no picture, a start that dies in seconds, and a machine that is actually reporting its fault with beeps and lights. Each family has its own first checks. Work through this page top to bottom, one change at a time, and note what the machine does after each step — that note is gold if the PC ends up on a technician's bench.
Do not open the cabinet yet. Press the power button once and observe like a witness: Is there any light anywhere — on the case, the keyboard, inside the vents? Do fans twitch, spin, or stay still? Any beep, click, or total silence? Does the monitor show its own logo or a no signal message, or is it black too? Then ask the most useful question in all of troubleshooting: what changed? The PC was moved, cleaned, a part was added, there was a power cut or a storm, a new device was plugged in. Half of all no-start cases confess right here.
Work from the wall towards the PC. Test the socket with a phone charger or a lamp — sockets and switchboards do die. If the PC runs through an extension board or spike guard, know that their switches and fuses fail quietly; try the PC plugged directly into the wall once. At the back of a desktop, find the power supply's own rocker switch and confirm it is on 1, not 0 — it gets bumped during cleaning and carrying. Finally, push the power cable firmly into both ends; a half-seated cable at the supply end is a classic. Laptops: try a second socket and look for the charging light before anything else.
This sounds like superstition and is not. Shut everything off, unplug the power cable (laptop: charger out), then press and hold the power button for 20 to 30 seconds. This drains the residual charge held in the board's circuits and resets a hung power-management state that can ignore the button completely. Wait a few seconds, plug back in, and try again. It costs nothing, risks nothing, and genuinely revives a surprising number of machines that looked stone dead — especially laptops, where this is the famous embedded controller reset in its simplest form.
Still dead? Power off, unplug, and open the side panel. Inside a desktop, three things quietly work loose: the RAM sticks, the big 24-pin main power connector, and the smaller 4 or 8 pin CPU power connector near the processor. Press each connector home with a firm, even push. For RAM, open the end clips, lift each stick out, and push it back until both clips click. Also glance at the tiny front-panel wires on the board's corner pins — if the power-switch pair has popped off, your button is connected to nothing. Full detail lives in the dedicated pages in this set; this pass is about reseating, not replacing.
If the machine powers but never shows a picture, reduce it to the smallest system that can possibly start. Unplug every USB extra — drives, dongles, printers — and leave only power, monitor and keyboard. Keep one RAM stick in the slot your motherboard manual names for single-stick use. If your processor has built-in graphics, plug the monitor into the motherboard's video port for this test even if you normally use a graphics card. A minimal system that starts tells you the core is alive, and you add parts back one at a time until the guilty one identifies itself.
On this final power-up, use your ears and eyes. A repeating beep pattern or a small debug LED stuck on one label (CPU, DRAM, VGA, BOOT) is the machine naming its own suspect — write the pattern down exactly. Fans that start and stop in a loop, or a death timed in seconds, point the other way, towards protection and heat. If the first checks fixed it, you are done. If they narrowed it down, the case pages in this set go one symptom deep each. If nothing responded at all, that is also a result: the fault is in the power path or the board itself, and that is bench work with spare parts — not a reason to start buying components on guesses.
Reading an order of checks is one thing — watching a dead PC being read, drained and reseated on camera is another. The full video walks through it step by step.
▶️ Watch Full VideoAt the wall, not inside the PC. Test the socket with a phone charger, bypass the extension board once, confirm the rocker switch on the back of the power supply is on 1, and reseat the power cable at both ends. Then do the leftover-charge drain: unplug, hold the power button for 20 to 30 seconds, plug back in and try. Only if all of that fails does the fault move inside the cabinet, most likely to the power supply itself.
No — a machine with spinning fans has power, so the problem sits further along: the picture path (monitor input, cable, wrong video port) or the start-up self-test stopping early, very often at the RAM. Check the monitor's input source and cable first, then reseat the RAM, then try the minimal boot with one stick described on this page.
Yes, with three rules: shut down and unplug first, never open the power supply box itself, and work gently without forcing connectors. If the PC is still under warranty, check the brand's terms before opening, because a free repair beats a brave one. And if you find anything burnt, swollen or smelling of smoke, close it up and hand it to a technician instead.