Chosen Solution

Error code= Boot Device Not Found Hard Disk (3F0) F2. System Diagnostics For more information. Please visit www.hp.com I have been thru the HP. generic troubleshooting B.S.. I have reseated the hard drive. I can run a “Memory Test"

Your OS is either not installed, missing or corrupted. You’re gonna have to buy another copy of Windows… I suggest Windows 10, since support for Win7 is ending. Also maybe check the drive’s condition, if it’s a spindle drive. Good Luck!