Computer turns off without warning
Tip: This document is for computers that remain off and not computer's that turn back on (restart) or computer's that turns off almost immediately after they are turned on.
Caution: Some of the steps below require you open your computer. While in the computer, be cautious of ESD.
Heat related issue
A computer that turns off without warning is usually caused by a heat related issue. Many computers today are designed to turn off automatically if the computer, processor, or other device gets too hot.
Start by verifying the fan on the power supply is working by examining the back of the computer and seeing if the fan is moving and moving smoothly. For all other fans in the computer, you need to open the computer and make sure the fan are working. While in the computer example the processor fan (heatsink), video card fans, and case fans. If you have heard any abnormal noises coming from your computer recently such as a high squealing, this is also a common indication of a fan failure.
Tip: While inside the computer it may also be a good idea to clean the inside of the computer. Dust, dirt, hair, and other residue in the vents and on the fans can prevent proper air flow and heat the computer.
Tip: If your BIOS monitors the RPM of the fans, enter BIOS and make sure the BIOS does not report any errors. Software utilities such as SpeedFan can also be used to help monitor fans in your computer.
While inside the computer, it's also a good idea to verify the processor heatsink is properly connected by disconnecting and reconnecting the heatsink. If the processor heatsink is not properly attached or does not have a proper amount of thermal compound, the computer will overheat.
Caution: If you do remove the processor heatsink the thermal compound on the processor and heatsink should be cleaned and new thermal compound should be applied. Not reapplying new thermal compound could make issues worse since the bond between the CPU and heatsink would be broken.
Hardware issue or error
Any failing hardware component in your computer could cause your computer to unexpectedly turn off without warning. If you have recently added any new hardware remove it from the computer to make sure it is not causing the problem.
Tip: Before attempting to remove any hardware, make sure you are not encountering this issue because of hardware conflicts by checking Device Manager for errors.
If you have not recently installed any new hardware into the computer, the next best solution to determining if this is a hardware issue would be remove any hardware on the computer that is not needed. For example, remove your modem, network card, sound card, and any other expansion cards that are not needed for the computer to operate. Run the computer without these cards to see if they are the cause of your issue.
Although not as likely as the above reasons, your computer to be infected with a virus or other malware that is designed to shut down your computer or turn it off. If your computer seems to be turning off when executing a certain program at specific times in the day, it could be infected.
If you believe your computer may be infected with a virus or are uncertain if your computer is infected with a virus, make sure your virus scanner definitions are up-to-date and it may also be a good idea to scan the computer for any other malware.
If after following each of the above recommendations your computer still continues to reboot, it is likely that you are experiencing a Microsoft Windows operating system related issue that cannot be explained. To help make sure this is the case, try the steps below.
- Reboot the computer and enter CMOS setup as the computer is booting.
- After you have loaded the computer in CMOS setup, let the computer sit.
If the computer does not turn off while letting the computer sit in CMOS, you are likely experiencing an issue with Microsoft Windows or your operating system and it is recommend you erase everything and reinstall Microsoft Windows.
If after reinstalling your operating system, or during the installation of your operating system, your computer turns off abnormally, it is very likely that other hardware is failing in the computer. Often this is RAM, CPU, Motherboard, Power Supply, or Video card (in that order).
If you have extra parts or have a friend or co-worker with a similar configuration that is willing to allow you to test their hardware in your computer, try swapping these parts to determine if they are at fault. Otherwise, you need to have the computer serviced.