Why won't my Windows laptop wake up from sleep?

First, rule out the screen

Sometimes Windows wakes but the display does not. Look for fan noise, keyboard backlight or the caps lock light. Press Windows key, Ctrl, Shift and B together, which resets the graphics driver, and unplug any dock or external monitor and try the laptop's own screen. If nothing responds at all, hold the power button for about 10 seconds, wait, and start it normally.

That hard shutdown is a recovery step, not a fix. If it keeps happening, work through the list below.

Find out what is going on with powercfg

Windows ships with a command-line tool, powercfg, documented by Microsoft, that reports on sleep behaviour. Open Terminal or Command Prompt as administrator (right-click Start, choose Terminal (Admin) on Windows 11, or Windows PowerShell (Admin) on many Windows 10 builds) and try these:

1. powercfg /availablesleepstates shows which sleep states your laptop supports and, according to Microsoft, tries to report why any are unavailable. Many recent laptops use Modern Standby instead of the older sleep state, and that changes which fixes apply.
2. powercfg /lastwake reports what woke the system from the last sleep.
3. powercfg /devicequery wake_armed lists the devices currently allowed to wake the PC.
4. powercfg /requests lists apps and drivers that are asking Windows not to sleep.
5. powercfg /sleepstudy writes an HTML report on Modern Standby quality, and powercfg /systempowerreport covers recent power transitions. Both save a file in the folder you ran the command from.

Run the first two straight after a bad wake or a spurious one, as they describe the last sleep only.

Fixes, in the order I would try them

Fix	Where	Why it helps
Update graphics driver	Laptop maker's support page, then Windows Update	Resume failures often involve the display driver
Update BIOS and chipset	Dell, HP, Lenovo, Asus or Acer support page for your model number	Sleep behaviour is partly firmware
Turn off Fast Startup	Control Panel, Power Options, Choose what the power buttons do, Change settings that are currently unavailable, untick Turn on fast startup	Removes one hybrid shutdown layer from the equation
Stop a device waking or blocking sleep	Device Manager, double-click the device, Power Management tab	Network adapters and USB devices are common offenders
Check wake timers	Control Panel, Power Options, Change plan settings, Change advanced power settings, Sleep, Allow wake timers	Prevents scheduled tasks waking the lid-closed laptop
Try a different sleep timeout and lid action	Settings, System, Power and battery (Windows 11)	Confirms whether it is specific to one trigger

Menu names shift between Windows 10 and Windows 11 versions, and some laptop makers add their own power utility that overrides these settings, so look for one in the system tray or Start menu.

If a particular device is the cause

If powercfg /lastwake or /devicequery wake_armed points at a device, you can stop it waking the machine with powercfg /devicedisablewake "device name", using the name exactly as listed; Microsoft's reference shows the syntax. Equally, if the laptop will not wake from the keyboard, the opposite command, /deviceenableawake, lets you check that the keyboard is permitted to. Do this one device at a time and test between changes so you know which worked.

When it points to hardware

Suspect hardware or firmware when the laptop fails to wake from every input, new drivers make no difference, and the failure survives a clean boot with only essential startup items. A failing battery, a loose RAM module or a faulty SSD can all disrupt resume. At that point, back up your files, check the manufacturer's support page for known sleep issues on your model, and contact support while you are still in warranty. For performance problems that show up alongside this, see why a laptop is suddenly slow, and if Wi-Fi is what fails after resume, Wi-Fi disconnects covers the adapter power settings.