If your computer won’t start after a power outage, you may end up searching for answers online. What you’ll find is hundreds or thousands of people having a similar problem without any definitive answers. This document offers a few possible ways to get your computer working again.

Force Start

To force your computer to start, even when the power button isn’t working, you might try pressing and holding the BIOS-FLBK button on the motherboard. This button is intended to be used with a USB flash drive for updating the BIOS. If no USB Flash drive is installed, the adjacent indicator light below the button will blink 7 times and the computer will start. So, this is an easy way to get around the problem.

The location of the button will depend on your motherboard model. The image below shows an example of what to look for. This example is for an ASUS P8Z77-V LE motherboard. This switch is found along the edge of the motherboard closest to the front of the computer. The image below shows a close-up of the lower right corner of the motherboard – assuming the computer is standing as a tower configuration. Or the far back right corner if the computer is flat and your view is from the back.

CMOS Battery

It’s possible that the battery on the motherboard needs replacing. You could remove the battery and use a battery tester, about $5 on Amazon. [View] Measure to ensure the battery has sufficient power. Or, since the batteries are fairly inexpensive you could purchase a battery and just see if that makes a difference. The CR2032 battery is available for about $5 in a 4-pack on Amazon. [View] First check to see which type of battery your computer needs and order accordingly, there are other batteries with similar appearance but slightly different size, so make sure you get the right replacement.

If you replace the battery, you may need to use the method above to force start the computer for the first time.

Check the Power Failure State

There is a setting in the BIOS that determines what the computer will do after a power failure. If that setting is configured for the computer to turn on automatically after a power failure, then it should turn on automatically when the power is restored. So, the computer should continue to restart itself, unless you request a shutdown from within Windows.

Motherboard Replacement

If the battery replacement doesn’t solve the problem, then it’s possible something is wrong with the motherboard. It could have been damaged from a storm or power store. You can replace your motherboard with a similar one.

New Computer

Some people may have just concluded that a power outage or storm damaged the computer. It’s not uncommon to have a damaged power supply that can result in a computer not starting. While a power supply is relatively inexpensive, installing one can be time consuming and involves removing the many wires attached to the existing power supply. Even with a new power supply, other issues in the computer could exist. So, some people would rather just replace an older computer at that point instead of putting more money into it.

What Other Are Saying

Here are some comments from forums that are representative of what others are saying:

“Today we had a power outage in my area. As a result my two computers lost power (yes I know I should get a UPS). One of them restarted fine and the other, a Shuttle XPC Model S141H, will not boot. When power is plugged in I can see a yellow and orange diodes come on through the grill but when pressing the power button nothing happens.”

[Source: SuperUser Forum, 2013]

and…

“Outage last night during a storm. … Power is back on and stable, I plug things back in, the motherboard lights indicating power are on (as seen in the images) and none of the built in ASUS problem light indicators are on. However the PC won’t boot at all, nothing happens. No fans, no blips, no flashes, nothing.”

[Source: Tom’s Hardware, 16 Jun 2017]

So, the recurring pattern is that a power outage can result in a computer not starting.