I have an XPS 8500 that will not boot normally. It was running fine and all of a sudden came up with the message "Reboot and select proper boot device or insert boot media in selected boot device and press any key". I have figured out if I go into BIOS first the PC will boot up but is very slow in doing so. I googled the issue and found something telling me to default the BIOS. I did this and it booted once. Trying to decide if the HD is out. I ran diagnostics and it does not see a HD. But if that's the case why does it even boot after going into BIOS. I am running Windows 10 Pro. I updated Windows 7 Pro. I am a strong believer in Dell and find it hard to believe that a HD would go out after only 4 years. Any help would be greatly appreciated.