Why does Windows restart without warning?
If your Windows computer is restarting on its own, without any warning, review the troubleshooting options below for help on resolving the problem.
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 may be nice for errors that do not occur often, users who have a re-occurring error may want to identify the error to troubleshoot it. 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 on My Computer. In Windows 8 and 10, open File Explorer and right-click on 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, unchecked 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.
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, it’s possible that the memory is bad in the computer.
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.
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 started up.
If you believe your computer has a virus, make sure an antivirus program is installed and the virus scanner definitions are up-to-date.