I'm suprised how anything didn't go wrong till now!

Run (chkdsk c: /r /p) before converting

then convert

Yes, you will loose with converting, and what you will loose will be problems.

I had...

Do not FORMAT  partitition!!!

Run Windows in Safe mode (press fast F8 in first moments of boot)

Start - Run - 'type' cmd

use command: convert c: /FS:NTFS

'(if your *mdf file is...