I'm working on my neighbors pc (HP Pavillion a720n). I get "DISK BOOT FAILURE, INSERT SYSTEM DISK AND PRESS ENTER" when attempting to boot. I tried the HD from my pc and it will go as far as the Windows boot screen then restart itself. I've checked that the cable is seated properly at both ends, checked in BIOS and it is detecting the drive and the boot sequence is ok. I reinstalled the original HD and ran the recovery console from the OS disk and attempted to CHKDSK and get the message "The volume appears to contain one or more unrecoverable problems". Any suggestions will be greatly appreciated.