FBF.
Much easier to get your data of by buying a USB drive caddy, putting your drive in it, and connecting it to another machine.
You could also run any tests on the disc like that. (Although nothing suggests that there is anything wrong with the drive).
Once you have the data safe, put the drive back in, and while the case is open check that every card and cable connection is fully home, and try a normal restart.
Cycling temperatures and vibration loosen connections.
If no go, then as GG said, safe mode and system restore should work if it's a software problem.