Debug | Restart
Click Restart on the Debug menu to stop the target's execution and end the target process and all its threads. This command then restarts the target execution at the beginning of the process.
This command is equivalent to pressing CTRL+SHIFT+F5 or clicking the Restart (Ctrl+Shift+F5) button () on the toolbar.
For more information about the effects of this action, other methods of issuing this command, and other ways to control program execution, see Controlling the Target. For more information about how to exit WinDbg or end the debugging session, see Ending a Debugging Session in WinDbg.