If you are able to boot the computer in safe mode, you can disable the Automatic Restart from the Control Panel.
Open Control Panel.
Click on the System and Maintenance link.
If you're viewing the Classic View of Control Panel, you won't see this link.
Click on the System link.
In the task pane on the left, click the Advanced system settings link.
Locate the Start up and Recovery area and click on the Settings button.
In the Start up and Recovery window, locate and uncheck the check box next to Automatically restart.
Click OK in the Start up and Recovery window.
Click OK in the System Properties window.
You can now close the System window.
From now on, when a problem causes a BSOD or another major error that halts the system, the PC will not automatically reboot. Rebooting manually will be necessary.
If you're unable to fully start Windows Vista due to a Blue Screen of Death error, you won't be able to disable the automatic restart on system failure option as described in the steps above.
Try the steps below:
Just before the Windows Vista splash screen shown above appears, or just before your PC automatically restarts, press the F8 key to enter Advanced Boot Options.
You should now see the Advanced Boot Options screen.
Using the arrow keys on your keyboard, highlight Disable automatic restart on system failure and press the Enter key.
After disabling the automatic restart on system failure option, Windows Vista might continue to load. Whether or not it does depends on what kind of Blue Screen of Death
or other problem Windows Vista is experiencing.
Since you disabled the automatic restart on system failure, Windows Vista will no longer force a restart when it encounters a Blue Screen of Death
Now that you have the STOP Code associated with the Blue Screen of Death, you can troubleshoot the problem:
The following is the list of BSOD error codes with troubleshooting, you can find the troubleshooting steps using the error codes in the MS website also..http://pcsupport.about.com/od/findbyerrormessage/tp/stop_error_list.htm
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