Windows 7 is configured by default to restart immediately after a Blue Screen of Death (BSOD) or other major system problem. This reboot usually happens too fast to see the error message on screen.
Follow these simple steps to disable the automatic restart feature for system failures in Windows 7.

Important: Unable to boot completely into Windows 7 due to the BSOD? See Tip #2 at the bottom of this page for help.

Here's How:

1. Click on the Start button and then on Control Panel.
   Tip: In a hurry? Type system in the search box after clicking Start. ChooseSystem under the Control Panel heading in the list of results and then skip to Step 4.
2. Click on the System and Security link.
   Note: If you're viewing the Small icons or Large icons view of Control Panel, you won't see this link. Simply double-click on the System icon and proceed to Step 4.
3. Click on the System link.
4. In the task pane on the left, click the Advanced system settings link.
5. Locate the Startup and Recovery section near the bottom of the window and click on the Settings button.
6. In the Startup and Recovery window, locate and uncheck the check box next toAutomatically restart.
7. Click OK in the Startup and Recovery window.
8. Click OK in the System Properties window.
9. You can now close the System window.
10. From now on, when a problem causes a BSOD or another major error that halts the system, Windows 7 will not force a reboot. You'll have to reboot manually when an error appears.
    
    
    

    BSOD (Blue Screen of Death)

    Definition: Abbreviated as BSOD or BSoD, the Blue Screen of Death is the popularized name for what is technically called a STOP message or STOP error. It's the blue, full screen error that often displays after a serious system crash. The text on the Blue Screen of Death may list any files involved in the crash including any drivers that may have been at fault and often a short, usually cryptic, description of what to do about the problem.
    
    
    courtesy:http://pcsupport.about.com