What might cause my computer to randomly shut down and reboot?
539808
This is due to hardware problem. Could be your video card overheating too. What are your system specs? Do you have any hardware monitoring tools in windows. I'd recommend Everest to monitor you temps until you can narrow what the cause is. In my experience, this is usually a vid card overheating, but it doesn't have to be that
653325
Reboot (restart) in safe mode, then go to  control panel/system/advanced tab/startup and recovery box/settings button/ sytem failure/ and   then uncheck  "restart on system failure" ( take the check out of automatically restart box )  , and then  check the "Write a system event", and the "Admin alert" boxes (check "send admin alert")  and  the next time it randomly turns off,  you should get a blue screen with white text, which will have code info.   Write down the exac Stop Error Code and put  that exact error into the google search box to see what info you get,  and/or  post that exact error here in this thread \n Also go to your device manager (devmgmt.msc) and check the properties  and look for anything suspicious and check that the settings are where they should be.
926786
This sounds as if your power supply on the PC itself went bad.  Especially if you have checked all your power connections, and you are still on getting power to your system.  \n\nyou may need to contact E machines and see if your system is stll under any warranty.  If you have any Geek friends, have them check it out to make sure its the power supply, and not the motherboard, memory, and/or processor.
877133
Could be a number of things ... if it's a virus you need to remove the hard-drive and "piggy-back" it into another computer for a complete virus scan \nIt could be the Thermal Grease on your CPU has dried out causing overheating, or a cooling fan not working that will shut most newish machines down or it could be something else hardware related
54967
I had a similar problem caused by an overworked power supply unit (PSU) which was cheap to replace, but in reality it's not going to be possible to diagnose over the internet as it could be any one of a number of hardware or software issues.\n\nMy advice would be to call some independent PC repairers. Some offer a no fix no fee service & should tell you up front what the cost is likely to be.
748477
try re-booting the system.
886218
install antivirus and check once....\nif u r getting a dialogue box saying that ur system is shutting down in 1 minute or something like that then\nopen command prompt\ntype shutdown -a
626697
Restart the PC. this kind of things sometimes happen.
122228
It may get overheated or some hardware is broken (it can be a HDD,RAM,Video card etc., I think the HDD has a problem). Try getting a hardware diagnostic tool.
361007
could be a hardware or heat related condition. if the fan for the cpu stops working, the cpu will get too hot and the computer will shut it's self down.
639372
Press the Ctrl, Alt, and Del keys simultaneously.\nPress them again.\nThat is called a "hot reboot" because the power is not turned off.\n\nShut down your computer.\nStart it up again.\nThat is called a "cold reboot" because the power is turned off.
628770
couple of ways to see if it is a hardware or a software fault\n\nfirstly boot into safe mode - restart your pc and keep on tapping the f5 or f8 key then select safemode\n\nleave it in this mode for a while - does it shut down ?\n\ncheck your event viewer for any system errors (in the control panel - administrative - then event viewer) click on the system \n\nsee if this gives you any clues\n\nalso try getting into the bios or cmos setup - again leave it in this mode - does it shut down - if so then you definately have a overheating problem\n\nalso check you in you bios to see if you have a hardware monitor option - if so check the cpu, system temp and fan speeds\n\ncome back to us with your results
674983
Have you done the regular maintenance stuff? Delete temp files (disc cleanup) and defrag? I would do that first. \nThen I would do another check by going to my computer, right click on C drive, click on tools, then check error checking check now. It won't do it until you restart. If that does not fix your computer then I would do the system restore.\n\nI would also run a spyware program to make sure you are not full of cookies.\n\nGood luck!
867880
I would guess the power supply failed.\nIf the hard drive spins up and you can tell it is booting up you may have a bad video card or a bad monitor.
47641
Check your start up programs.\nSTART > RUN > type MSCONFIG > STARTUP uncheck things you really do not started at Boot up.
921256
could be something wrong with your PC
958302
yea this has happened to me before i think it has to do with your power supply, is this an older PC?  Pretty sure its the power supply shorting out a Lil and making it think its restarting