A desktop PC can sometimes start without its case power button by using a motherboard start button, a working replacement switch, or a previously set up wake feature. The right method depends on the motherboard. A broken case button is only one possible cause of a PC that will not start.
First check whether the button is really the problem
Check the wall socket, power cable and the power supply’s rear switch. Note whether pressing the case button does nothing, briefly starts the fans, or starts the PC without a picture. These are different symptoms. ASUS‘s no-power and no-display guide separates the main hardware checks.
If fans run but the screen stays blank, use our motherboard diagnostic-light guide. Bypassing the button will not fix every startup failure.
Choose an option your motherboard supports
| Method | Works without earlier software setup? | What to check |
|---|---|---|
| Motherboard Start/Power button | Usually, if the board has one | The exact board manual and a clearly labelled start button. |
| Replacement case power switch | Yes, with the correct front-panel connection | The PWR_SW/PWRBTN header in the board manual. |
| Wake-on-LAN | Usually needs earlier setup | Network adapter, firmware, Windows and supported power states. |
| Power on after AC power returns | Needs the firmware setting enabled | Restore AC Power Loss or the equivalent option. |
Use an onboard start button if one is fitted
Some desktop motherboards have a Start or Power button on the board. Check your model’s manual before opening the case. A button marked Clear CMOS, BIOS Flashback or Reset does a different job.
“ASRock bypass power button” is not a single procedure for all ASRock boards, and the same applies to ASUS, MSI and Gigabyte. Use the model name printed on the board to get the correct manual.
Check the case-switch connection or fit a replacement
The case button connects to a small front-panel header. With the PC shut down and disconnected from mains power, check whether that cable is loose, using the manual’s exact pin diagram. Reconnect it only to the documented power-switch pins.
A compatible momentary replacement switch connected to those pins is a practical fix for a failed button. Do not copy a pin layout from a different motherboard or short random contacts with a screwdriver. If you cannot identify the header confidently, have a technician check the switch and cable.
Wake-on-LAN: useful when it was set up in advance
Wake-on-LAN lets a supported network adapter respond to a wake packet while the PC has standby power. Firmware and operating-system settings both matter, and waking from sleep is not the same as starting from every shutdown state. Follow the manufacturer’s instructions, such as ASUS’s motherboard Wake-on-LAN guide.
Start automatically after AC power is restored
Some boards offer Restore AC Power Loss, AC Back or a similar setting. ASUS documents Power Off, Power On and Last State as different choices. This is useful for a planned setup; it cannot help you enable the option on a PC that you cannot currently start.
Shut Windows down normally before any planned power disconnection. Repeatedly cutting mains power while it is running is not a substitute for repairing a failed switch.
Updated October 15, 2026. Reviewed using the sources linked in this guide.