Mid 2011 27" iMac Not Booting, Worth Repairing?
I have a mid-2011 27" iMac with a 3.4GHz i7 processor. I run both OS X 10.12.6 and Windows 10 (via Bootcamp partition). The other day I was in W10 and generating some spreadsheets. All seemed to be well, but I stepped out of the room for a moment, and when I returned the screen was dark. It wasn't sleeping, or I couldn't rouse it, so I did a hard shutdown and was unable to restart. It won't boot. No startup chime, just a sound from the DVD starting, and the fan runs, but the screen remains dark. If I had to guess, I'm thinking the video card is toast.
Two questions:
I spoke with Apple support over the phone, and they ran me through the usual steps, and I now have a Genius Bar appointment. Is there anything their in-store diagnostic software is going to tell me? I've watched them work on other machines, and it seems like the non-booting status here means I'd be wasting my time (and theirs) visiting the store.
I do have a 21.5" machine, same vintage, with a HDD where the OS X partition fails the Genius Bar diagnostic, but the machine will boot into the Bootcamp W10 partition, and is otherwise functional. I'd like to collect a few files off my 27" iMac's W10 partition, since my last backup is a few days old. Can I swap out the HDDs and get them?
Thanks in advance, sorry to go on at such length.
iMac (27-inch Mid 2011), OS X Yosemite (10.10.4)