To boot the Command Prompt on a Dell PC or laptop, repeatedly press the 'F12' key after turning on your PC and seeing the Dell splash screen. This procedure displays boot choices, including CD/DVD, USB, HDD, LAN, and SSD. If you don't have boot repair media, repeatedly press the 'F8' key, and you may get the 'Advanced Options' menu. Next, choose to boot to Command Prompt from the Advanced Options screen.