OK, I'll try to be as detailed as I can with this. Originally, I was trying to size down my system partition in order to clone it onto my SSD, by clearing as much space as I could, then creating a second partition and moving non-system files over, resizing when needed (only had to be done three times). The first resize went off without a hitch, but the second one ended up completely botching my Windows installation to the point where it was unusable and unrecoverable, so I had to resort to a fresh install of Windows 8 straight onto the SSD (which I know is the recommended method; I just didn't want to resort to reinstalling every single program of mine again). Now, since then, everything's been fine, except for the former system partition on the HDD. It refuses to let me browse it (as seen in the screenshot above). Weirdly however, I can see the folders if I explore it in EASEUS Partition Master. Now, I have Google searched to try and find a solution; the common one that pops up is to grant all privileges to my account, which has already been done. Another suggestion was to convert it to a dynamic volume, but that hasn't worked either (and annoyingly, I can't convert it back to a basic volume now). I've also done a S.M.A.R.T. check, ran CHKDSK, ran SFC /scannow, all they all come back with no issues.
Does anyone know any other potential solutions for regaining access to the drive, without losing any of the files? A fair bit of my personal stuff is on there (documents, pictures), as well as a lot of Steam game files; I really don't want to have to resort to redownloading several hundred GBs again.
Obviously, I have been an idiot for not having a backup; I'm planning on rectifying that by buying an external HDD soon; preferably a 2TB one, so I can back up both HDDs.