Hard drive not installed or a no boot device error? First step is to run diagnostics. Restart the system and at the Dell splash screen start tapping F12. Run full system diagnostics paying attention to the hard drive results. If it is a no bootable devices, the following forum posts may help.
Thank you for your message. What is the status of the hard drive in BIOS? Is the hard drive detected fine?
Do you get any error message on Dell Support Assist?
Does the system boot fine when you restart the computer or do a hard shutdown?
For my reference, please click on the message tab next to your avatar– click “New Message” & search for my Dell username (Dell-Sreejith R) & send a private message with the service tag, registered name & email address.