Why does Windows restart without warning?

Updated: 06/30/2020 by Computer Hope

If your Windows computer is restarting by itself without any warning, review the following troubleshooting steps for help on resolving the problem.


This page is for computers that are restarting by themselves, not computers that turn off and remain off. For computers that remain off, see: Why does my computer turn off without warning?

Software issue or error


Since the release of Windows XP, Microsoft designed Windows to automatically reboot when errors occur, such as a BSoD. Although this feature is nice for random errors, it does make it difficult to troubleshoot. Below are the steps on how this feature can be disabled and enabled in Windows XP, Vista, 7, 8, and 10.

  1. From the desktop, right-click My Computer. In Windows 8 and 10, open File Explorer and right-click This PC in the left navigation pane.
  2. Select the Properties option in the pop-up menu.
  3. In the System Properties window, click the Advanced tab or the Advanced system settings link.
  4. On the Advanced tab, click the Settings button under Startup and Recovery.
  5. In the Startup and Recovery window, uncheck the Automatically restart check box.
  6. Click OK.

Now, if the computer generates an error, it should not automatically restart and should display an error message, most likely a BSoD.

Hardware issue or error


Some of the steps below require you to open your computer. While working inside the computer, be cautious of ESD.

Any failing hardware component in your computer could cause your computer to generate an error or reboot without warning. If you have recently attempted to add a new hardware device, remove that device to make sure it is not causing your issues.

Make sure you are not encountering any hardware conflicts by viewing Device Manager for errors.

Hardware drivers can also cause this issue. If you have recently installed new hardware drivers, you may want to try an earlier version of those drivers. Additional information and help with computer drivers is available on our drivers page.

If you updated drivers and removed any newly added hardware and the random reboots continue to occur, the computer memory is bad.

Finally, hardware devices that are not installed properly in the computer can also cause random reboots. Make sure all the cables and expansion cards are connected properly inside the computer. The best way to determine this is to disconnect and reconnect all cables and expansion cards.

Computer virus

Computer Virus

Some computer viruses, such as the blaster virus, are designed to reboot your computer without warning. Usually, these viruses make the computer reboot every 5, 10, 15, or 30 minutes after the computer has boot.

If you believe your computer has a virus, make sure an antivirus program is installed and the virus scanner definitions are up-to-date.

Heat-related issue

Temperature gun monitoring computer CPU

Most computers today are designed to turn off or automatically reboot if the computer processor, video card, or other devices in the computer get too hot. If you have heard any abnormal noises coming from your computer recently, it could be a sign of a failing fan, which can cause hardware components to overheat.

First, verify the fan on the power supply is working by examining the back of the computer. Check if the fan is moving, moving fast, and moving smoothly (e.g., not wobbling or scraping against the insides of the power supply). For all other fans in the computer, you need to open the computer and verify all fans are working (e.g., processor fan, video card fan, and case fans).

A temperature gun, like the one shown in the picture, can gauge how hot the hardware components or integrated circuits are inside the computer.


If your BIOS monitors the speed, or RPM, of the fans, enter the BIOS setup and verify it does not report any errors. For help getting into BIOS setup, see: How to enter the BIOS or CMOS setup.


If this is a laptop computer, there is often a fan on one of the sides of the laptop. Make sure this fan is blowing air out of the laptop and check if you can feel hot air coming from the laptop. You may also consider getting a cooling pad if your laptop is getting hot often. For further help, see: What should be the temperature of my computer processor?

Issue with the operating system

If, after following the recommendations above, your computer continues to reboot, you're likely experiencing an issue with the Microsoft Windows operating system. To help determine if this is the case, try the steps below.

  1. Reboot the computer and enter BIOS setup when the computer begins to boot up.
  2. After you have loaded the computer into the BIOS setup, let the computer idle for a few minutes.

If the computer doesn't reboot after idling in BIOS and you've tried the other solutions above, try activating a restore point in Windows before the problem started to occur. If activating a previous restore point does not work, or there are no restore points available to activate, you likely need to reinstall Microsoft Windows.

Additional information