I'd try this from Linux, a LiveCD or LiveUSB next (no install.)
My 4yr old Dell laptop died recently, so I pulled the HD, installed it in a 2.5 SATA /USB 3.0 enclosure, and expected to use the drive as an external storage device and also retrieve files I had not yet backed up. To my surprise, he recovery partion is accessible, but the primary partition loads very slowly in file explorer(win8), and ultimately fails as 'drive not accessible'. I've also pulled it up in disk manager, but it shows the drive space with no file system, and ALL the space available (250G). It almost like it's unformatted.I'm assuming the drive is physically still functional or the recov partion would not work.
Anyone have any ideas? Thanks!