Windows 7 randomly changes OS drive letter and becomes unbootable HELP


Mar 10, 2015
About 2~ weeks ago, when I restarted my computer, it didn't boot normally.. instead it went to a black screen which says "loading windows files" and then it opens the system repair menu. On this menu it says that windows is on E:\. It doesn't detect any system restore points (I know I had some), and system repair does nothing. The bootrec commands (/fixmbr /fixboot) run successfully but do nothing, and /rebuildbcd and /scanos both detect 0 windows installations..

Today this happened again, and I could not figure out how to fix it (I tried bootrec again and I tried Hirens bootcd, but I didnt know what I was doing so I didnt accomplish anything with that.) so I had to reinstall windows again.. wiping my C: drive.... again.

My partitions in order when this happens: (according to cmd /listpart)
Part 1: 100MB reserved system partition on my OS drive gets assigned drive letter C:\ (I think it should have no letter?) this is the active partition and its labelled as a system drive
Part 2: My second non-OS HDD is assigned D:\ and is also labelled as a system drive
Part 3: My main OS drive (SSD) gets assigned E:\ and is labelled as primary drive

/listdisk lists my two drives normally

list of things I've tried that didn't work:
-The bootrec commands in cmd
-bcdedit /export C:\BCD_Backup->c:->cd boot->attrib bcd -s -h -r->ren C:\boot\bcd bcd.old
-F: ->cd boot->dir->bootsect /nt60 SYS /mbr
-most of the MBR/Partition programs in Hirens... I didnt have a clue what I was doing so I just clicked on all the options that seemed like they could possibly fix this automatically
-swapping the drive letters around in the command prompt, the disk management program in Hirens MiniXP, and regedit
-virus scan in Hirens minixp(though I cant update definitions due to no internet in minixp and it wont let me use most of the AV programs)

I have no idea how to prevent this, and what to do about it other than reinstalling windows..... please help

Gary Price

Aug 17, 2014
With a boot disk loaded in your dvd rom find the hard drive tool to scan your hard drive for problems. I'm assuming it's probably not bad sectors because you were able to wipe it. But I would check anyway.