My computer will not shut down.when i try to shut it down it reboots.

First - re-seat the hard disk and reboot the computer. If the computer does not boot up then reboot and go into the BIOS configuration to see if the BIOS detects the hard drive. If it doesn't detect the hard drive then it could be faulty.
Then the hard drive needs to be replaced in the computer/laptop, Windows installed and the computer or laptop's device drivers plus your programs etc. to get a functioning computer/laptop again.

See if this helps...
http://www.pcworld.com/article/247392/my_computer_reboots_when_i_tell_it_to_shut_down.html
or this...
http://social.technet.microsoft.com/Forums/windows/en-US/60526fa7-2864-40fb-abd6-8e314ebcb73e/windows-7-reboots-when-i-try-to-shutdown?forum=w7itprogeneral

Reboot essentially means restarting the computer. This is two types
1. Warm Reboot: where you go to start on windows task bar and choose shut down but when prompted choose restart. This way computer shuts down momentarily and restarts!
2. Cold Reboot: By this means you choose to shut down and again when prompted choose shut down! This makes computer off completely until restart by pressing power button.
Booting is computer Lingo for above procedures!

try a hard shut down by holding power button down till computer shuts off. if this doesn't work unplug from power source and see if you can reboot. of can't reboot. may have problem with mother board. this then goes beyond my scope.

hi sir,

Does it just shuts down or it reboots?
If it shuts down this type of problems can be resolved by scanning the computer for a virus or
using the Windows Repair Disks. During boot if you can hit F8 and use safemode with command and prompt.

1 Type CHKDSK/F then hit enter
2 Press Y then hit Enter then reboot to see if this works.

If it reboots while booting up then.

Other things that might be preventing the computer to boot up most likely is the memory.
Take out the memory put it on a different slot or try a new memory.
Also make sure that the power supply fans are not dirty this prevents the computer to bootup.

Supose you have allready tryed to change "restart the computer" to "shut down the computer" when you shut down the computer?
 
/Teis

The most common shut down problem is that the system will reboot rather than shutting down. In most cases, the reboot is triggered because Windows XP is designed to reboot after a critical failure. To stop windows from rebooting in case of a failure, you need to take the following steps:
Right click on My Computer, Select Properties, Click on advance tab, Click on Settings under Startup and Recovery, Uncheck the option Automatically Restart under System failure, Click Ok twice and try to shutdown the pc. If it shows any error code then let me know

try CONTROL+ALT+DEL
select Shut Down
then Turn Off or Restart

*if your computer is malfunctioning or corrupt or frozen.
Theres alway the manual shut down way
HOLD POWER BUTTTON FOR AT LEAST 6 to 10 seconds or until computer shuts down. Then turn on computer and try again.

Hi there...
              MMMMMmmmmmmmm can you be more specific ? has it recently started to do this or has it done this since you purchased the computer ? Are you trying to shut it down from the windows shutdown menu or are you pressing the power button to let windows shut it down ?? I Need more information before I can help you work out whats going on with your computer ...If its only just started to happen you may have a virus or a trojan infecting your system or your bios has become corrupted.The windows registry may have become corrupted or your power supply is faulty...the problems that could cause this are numerous , please be more specific about how you are shutting the computer down..
 

unistall recently installed hardware or software and try otherwise format the system and reinstall operating system it work ok, till the same problem if you have two rams remove one ram and check