My Dell Precision 690 workstation has stopped booting into Windows 7 altogether.
About a week ago, the BIOS started giving me a message that the amount of memory had changed from the default configuration. I thought this strange for a couple of reasons, the biggest of which being that I had done absolutely nothing to the configuration or even to the computer itself. No problems yet, it still booted fine.
Two days ago, however, it stopped booting to Windows altogether, telling me that there is "No boot device available." The BIOS lists the two SATA HDDs that are connected, but won't boot to either, giving the aforementioned error message.
Would this be a Windows error or a hardware error?
UPDATE: As I was writing this question, the computer allowed me to boot to Windows Startup Repair. As I have not created a restore point myself, I had to choose to use Startup Repair. After restarting, the number of SATA devices listed in the BIOS on startup increased from 2 to 9, and again showed me "no boot device available."
My problem is actually fairly similar to the problem described here, with the exceptions that it is more common for the computer NOT to boot to Windows and that these are standard HDDs, not SSD.
Another UPDATE: This is an example of what I get on startup. Shortly thereafter, the table is replaced with the "No boot device available" error.

