due to a recent Windows 8.1 update, my boot partition C: was rendered unusable. Luckily, I had a backup from a month ago on an external drive. I tried restoring it by Easeus ToDo backup, but it got stuck at 68% several times. I managed to salvage all the data from the backup by partial restores, so I have the whole partition back on my hard drive.
Meanwhile, I installed a fresh Windows 8.1 instance on my C drive. I had the restored backup of my old Windows on drive E. I was able to boot into it, but it did not let me use my profile I used before the crash - files there was mapped to a C: drive, including the users directory (when I moved the E:/users directory into C:/Users, I was able to sign under my profile, but everything else, it being mapped to the C:/ drive, didn't work).
So, I was thinking about switching the drive letters. The C: letter can not be switched using diskmgmt, and I also tried to work with HKEY_LOCAL_MACHINE\SYSTEM\MountedDevices. While I was able to switch some drive letters around on non-bootable partitions, changing the letter on my E:/ drive caused it to not boot anymore, serving me a "Critical device failure" error.
I am at the end of my rope here. I was thinking about installing windows to a new partition, and forcefully copying the whole backup there, I dunno. Could someone help me out, please?