My computer shuts down at a certain time

Please run system file check:
SFC /SCANNOW Command - System File Checker

If it is BSODs, make sure you have set system to create minidump file for further analysis:
Windows 7:
Go to Start and type in "sysdm.cpl" (without the quotes) and press Enter
Click on the Advanced tab
Click on the Startup and Recovery Settings button
Ensure that "Automatically restart" is unchecked
Under the Write Debugging Information header select "Small memory dump (64 kB)" in the dropdown box
Ensure that the Small Dump Directory is listed as "%systemroot%\Minidump" (without the quotes)
Click OK twice to exit the dialogs, then reboot for the changes to take effect.


Follow this instruction:
https://www.sevenforums.com/crashes-d...tructions.html

ttran gave some excellent advice, so give that a try for sure.

Does it shut down properly? Or does it just turn off?

You might also check in the BIOS and see if there is anything pertaining to auto shutdown or restart. Many computers have a timer setting to have the computer do stuff like that automatically at a predetermined time. :)

if it shuts down properly, check the power plan, see if it is set to turn off the computer at a certain time.
also, check your bios, it might have a setting in there that shuts down the computer at a certain time.

so, it just hard boots? no proper shut down?
ok when you first start up your computer, you'll have to press a certain key to access the bios.
Usually it'll be the Delete key. Sometimes it'll be F2. If you could post pics of your bios, then i might be able to help you find the option, if it's there.
You'll have to press these keys repeatedly as soon as you power on your computer.