Just follow the below steps and problem will solve:
1. Right Click on My Computer.
2. Click on Properties.
3. Now the systems properties will open. Click on Advanced Tab.
4. Under the Startup and Recovery section, press on settings.
5. The start up and recovery box will appear. Go to the System Failure section.
6. Uncheck the box where it says Automatically restart.
7. Press ok to finish.
Now your problem is solved for ever...