The continuous reboot problem can have a variety of causes, including faulty or unseated memory modules; out-of-date, corrupt, or missing drivers; software conflicts; overheating components; virus or malware; bad software; or bad hardware.
Hardware.
Your computer may immediately fail to boot if one of your memory modules is unseated. The memory modules are long, narrow sticks that attach to the motherboard located near the processor and have clips at either end. If one or both of the clips is not closed or laying flat against the edges of the module, press down on the edge of the nearest to the clip. You may have to remove the memory module and reseat it.Restart the computer.
Your computer may also immediately reboot if another piece of hardware fails, has a loose connection, or becomes disconnected. Check that power plugs from your power supply are connected to the appropriate components and that those connections are secure. Listen for your hard drive to start spinning. If it is silent, then it may be faulty or disconnected from the motherboard. Also, be sure the fans on your motherboard or graphics card start spinning. If any component seems unresponsive, replace it.
BIOS.
If the settings in the BIOS have changed or become unstable, you may need to reset the settings to get your system to boot again. Restart your computer and access the BIOS setup utility. When you have access to the BIOS setup utility, you should see options to Load Defaults, Load Optimized Defaults, Load Fail-Safe Defaults, or something similar. First, try loading the Optimized Defaults. If your computer still fails, re-enter the BIOS and load the Fail-Safe Defaults. If you don’t have a choice, simply load the default settings as described in your computer or motherboard manual. Confirm your choice and allow the system to reboot. You may have to select the Save And Exit option to restart your system.
Sometimes, your computer won’t even let you access the BIOS. In these instances, you may have to reset the BIOS using a more hands-on approach. The CMOS (complementary metal-oxide semiconductor) memory retains your computer’s BIOS settings but can be reset by moving a jumper on a three-pin header on the motherboard and then moving it back to its original position after a short wait. You’ll have to consult your computer or motherboard manual for specific instructions on how to perform this operation.Restart the computer. Restarting sans error message.
Virus or Malware
If your system is infected with a virus or malware or experiencing system-crippling errors, you may never see error messages that can provide clues as to why your computer continuously reboots. Windows is set to reboot when it encounters a critical error. Disabling this can let you view error messages and on-screen prompts. To change the setting, boot into Safe Mode and access the Control Panel, click Performance And Maintenance and click System from the bottom of the dialog box. Click the Advanced tab and then click the Settings button from the Startup And Recovery section of the System Properties dialog box. Next, deselect the checkbox in front of Automatically Restart in the System Failure portion of the dialog box. Click OK and click OK again. Close the Control Panel and restart the computer. Now, when your system encounters an error, it will remain on-screen.