How to open Command Prompt on Windows 10 startup
You desperately needed the command prompt when installing Windows 10 from a disc or flash drive, even before the operating system was successfully installed. In some situations, the command prompt can be very useful for system recovery. Simply boot from any convenient source (disc or flash drive), then press Shift+F10 on the first Windows 7 installation screen. After pressing this key combination, the command prompt will open, and you can do whatever you want with it.