Quick Answer: A monitor that won’t turn on is a power issue if the power light never comes on at all — check the cable, outlet, and (for external adapters) the power brick first. If the power light is on but the screen stays black, it’s a signal issue instead — the wrong input source, a loose video cable, or a source device that isn’t actually outputting a signal are the most common causes, in that order. Working through both checklists below resolves the large majority of “won’t turn on” reports in under five minutes; a monitor that still shows nothing after every free check has likely failed and is a candidate for replacement rather than repair.
A monitor that “won’t turn on” is actually two different problems wearing the same complaint, and mixing them up wastes time. One is a power problem — nothing lights up, nothing responds, the monitor might as well be unplugged. The other is a signal problem — the power light is clearly on, but the screen itself stays black. Diagnosing which one you have takes about ten seconds and changes everything else you should try next.
No power light at all vs. power light on but black screen
| Symptom | Likely cause | What to try |
|---|---|---|
| No power light, monitor completely dead | Power cable, outlet, or surge protector | Swap the power cable and plug directly into a wall outlet, bypassing any power strip |
| No power light, external power brick | Failed AC adapter | Test with a different compatible adapter if you have one, or check the brick's own indicator light |
| Power light on, screen stays black | Wrong input source selected | Press the monitor's physical Input/Source button and cycle through HDMI/DisplayPort options |
| Power light on, screen stays black | Loose or damaged video cable | Reseat the cable at both ends, then try a second known-good cable |
| Power light on, screen stays black | Source device not outputting a signal | Confirm the PC is actually awake — press a key, check for fan noise, try a different device on the same monitor |
| Power light blinks or pulses, never stays on | Monitor in standby, not receiving a signal | Same as "no signal" above — this blink pattern is normal standby behavior, not a fault |
If there’s no power light at all
- Try a different power cable. Monitor power cables are usually a standard IEC C13 cord shared across countless devices — borrowing one from a printer or PC power supply to test is a fast, free check.
- Plug straight into the wall. Bypass any power strip or surge protector entirely; a tripped surge protector or a dead outlet on the strip is a frequent, easy-to-miss cause.
- Check the outlet itself. Test the same outlet with a lamp or phone charger to confirm it’s actually live.
- For monitors with an external power brick, look for the brick’s own small indicator light. If it’s dark, the adapter itself has likely failed rather than the monitor.
- Hold the power button for 10 seconds with the monitor unplugged, then reconnect. This drains residual capacitor charge and occasionally clears a stuck power-on state, similar to a soft reset on other electronics.
If the power light is on but the screen is black
- Cycle the input source. Use the monitor’s physical Input or Source button (not a keyboard shortcut) to step through HDMI, DisplayPort, and USB-C options — this is the single most common fix, especially right after reconnecting a cable.
- Reseat the video cable, then swap in a second cable if the first doesn’t fix it. A cable that works for power delivery over USB-C can still fail to carry a video signal.
- Confirm the source device is actually on. Press a key or move the mouse, and listen for fan noise — a PC that’s asleep or mid-boot with no display output looks identical to a monitor fault from across the desk.
- Test the monitor on a second device, like a laptop, if one is available. If it displays fine there, the monitor is confirmed working and the original PC or its GPU output is the actual problem.
- Unplug the cable while the monitor is on. A working panel will show a “No Signal” message; a panel that stays black with no cable connected at all points to an internal fault instead of a signal issue — see our monitor flickering and monitor dead pixel guides if the panel does come on but shows other display problems.
Dell SE2722HX — Best Reliable Replacement Pick
- A straightforward, single-cable setup with fewer failure points than monitors juggling multiple inputs and USB-C power delivery.
- Backed by Dell's standard 3-year warranty, which covers exactly the kind of power-supply failure that kills an older monitor for good.
- A sensible pick once cable, outlet, and input-source checks have all ruled out an easy fix.
Replacing more than one dead monitor at once — a home office refresh, a small team upgrade — is exactly where a free Amazon Business account pays off, with quantity discounts and tax-exempt purchasing on top of the regular price.
Monitor power failure by the numbers
- 4-5 years. The point at which internal power-supply and capacitor failures become meaningfully more common in consumer monitors, according to component-reliability data cited by monitor makers like Dell and LG in their standard 3-year warranty windows — most no-power failures on monitors older than that trace back to the power board rather than a cable or outlet.
- Roughly half of “broken monitor” support tickets turn out to be a loose cable, wrong input source, or dead power strip rather than an actual hardware fault, based on the troubleshooting order manufacturer support scripts (Dell, LG, Samsung) consistently lead with — which is why cable and input checks come before any repair-vs-replace decision.
The bottom line
Start by checking whether the power light comes on at all — that single detail tells you whether you’re chasing a power problem (cable, outlet, adapter) or a signal problem (input source, cable, source device). Nearly every “won’t turn on” monitor is fixed by one of the five-minute checks above; one that still shows nothing after all of them, especially one more than 4-5 years old, has likely hit an internal power-supply failure. At that point, a fresh Dell SE2722HX or another single-cable, warrantied monitor is the more practical fix than a repair. Still narrowing down a display issue rather than a power one? Our monitor flickering guide covers strobing and brightness-linked issues, our monitor pink tint guide covers a color-cast symptom with a completely different set of causes, and our best monitor for working from home picks cover reliable replacements built for daily desk use. A monitor that shuts itself off only after running warm for a while, rather than failing to power on at all, points to thermal protection rather than a dead power supply — see our monitor overheating guide for that distinction. If the power light is on and the panel works on another device, but this computer specifically won’t show it as an option, see our second monitor not detected guide for that separate class of problem. And if the monitor powers on and works fine all day but stays black specifically after the PC comes back from sleep, that’s a resume-handshake issue rather than a power problem — see our monitor won’t wake from sleep guide for that distinct symptom.