The guide button on either the game controller or the DVD player remote will restart the console if it is pushed during gameplay. Make sure not to hit this button when you use the controllers for games. If the console restarts without you hitting the guide button, try using a different controller. This should solve the problem if you have a damaged or defective controller which may be returned to the location of purchase for a replacement or refund.
Broken On/Off Button
If the on button is depressed during play, your console will restart. The on the button may be defective, however, and restarting your game without any input from the user. This is normally the result of a broken switch in the console and will need to be addressed by a certified Microsoft repair technician. The location where you purchased the 360 may be able to inform you of a local repair tech and whether or not your warranty covers this repair. You can also call Microsoft Xbox 360 support at (800) 4MY-XBOX.
Hard Drive Incorrectly Installed
Sometimes, an error in construction at the factory or in transit may have dislodged the Xbox 360 hard drive. This will cause random reboots whenever the hard drive loses connection to the unit. Unplug your console and remove the hard drive bay cover. Press the hard drive in, and then pull it out of the console. Realign the hard drive with the narrow end directed at the front of the console. Push the drive-in firmly; do not stop until you have heard the click that signifies it is in place. Check to ensure that the drive fits snugly and does not wiggle after the click. If it wiggles, contact Microsoft support as above.
Disconnected or Damaged Disk Drive
If you notice any strangeness with the DVD drive on your Xbox 360, this is likely to be the cause of your reboots. Any disconnect in the connections between the drive and the console will cause an automatic reboot as it assumes a new piece has been added or removed. Often this will be obvious as the drive will eject without notice or spin noisily. You can set up a repair service call through Microsoft’s Official Xbox Contact Information page as well as shipping pick up.
There are a number of other, less common, reasons that your Xbox 360 may randomly restart. Check all cables for obvious signs of damage or wear, especially at any bends or corners. If your console is connected to a surge protection device, verify that it is functioning normally and the breaker has not been tripped. If you are still not able to find the source of the restarting problem, contact Microsoft Support either through their email form or by telephone. You can also find more about the solution to these common Xbox problems by clicking on Domino99 Online. Along with that, you will find tons of online games that you can try as you resolve your Xbox issues.