For starters, try disconnecting the SATA data cable from the ailing HDD. If the OS really is on the SSD, does the PC boot now?
Wife has an XPS 8920, standard install from Dell (no OS re-installs, etc.). Has a 256G M.2 SSD, and a 2TB HDD. Warranty expired. Dell threw an error (2000-0150, status #48), but searches so far are pretty nebulous "hard drive failure" and not more specific. As far as I can tell, it is set to boot from SSD. Not sure what HDD was used for. Booted live linux into gparted, and as far as I can tell, the SSD is ok (bunch of partitions including boot and OS), and the HDD is the one with the problem. It SEEMS like Windows boots and it tells me it's starting auto-recovery option, but that screen never seems to get anywhere... Some questions I hope that can get me started trying to recover the system and/or data (I've not worked on PCs low level for 10+ years, I run unix servers these days): 1) If the SDD is the boot, then why is an HDD fail not letting it boot? Maybe theres swap there? Is there a way to get around that? 2) Are there any good documents describing this Dell configuration (SDD boot and HDD.... ??? with BIOS Raid on), that might give me some starter background and potentially ideas on how to solve this issue? She doesn't need the HDD that I'm aware of (I have a NAS for our files), she just needs to get the OS booted up again. Thanks for any help! Will be attempting some google searches on this, but as the DW wants immediate help, posting here too...
XPS 8920, drive and boot failure