New behavior: Windows would begin to boot up (past logo) and then switch to the black screen "sorry, Windows failed to start for some reason, please try again..." All the variations I could come up with (safe mode start, safe with networking, reset button, F8-to-safe before logo, etc.) all had the same result.
A tech/admin friend mentioned the heat/rattle combo might be heat-related expansion jamming the R/W head. On his advice, I put it in the freezer (!) for a few hours, then hooked it up. Nothing new.
I installed the new HD, and attempted to look at the broken one from there. A window popped up with, "Drive E:/ is not formatted, would you like to format now?"
Some of the important data was not backed up before the crash. I did not want to take the chance of wiping all the data from the HD, so I did not format.
o Will formatting the drive allow me to access the data?
o Will formatting the drive wipe out all data?
o Are there data recovery tools I might use?
o Is there something I should be doing, but am not?
o Is there something I am doing, but should stop immediately?
Thank you for any help or advice you can give me.