Which operating system?
Which version of Photoshop? Are background save and auto-recover enabled in Photoshop?
Do you have any backup strategies in place on your PC?
e.g. AJC Active Backup automatically backs everything up to the last keystroke
If you never saved it. Your document was never a file so there is no file you can get back. If you have CS6 or newer you should set your Photoshop preferences to autosave recovery files. If there is a crash when you start Photoshop the next time Photoshop will open any PSB it finds in your user id AutoRecover folder to help you recover your unsaved work.