Es war nur eine Primäre Partition -> NTFS
300 MB auf 400 GB sind ja nicht tragisch.
Es geht eher um den Rest.
Damage Assessment
Let's suppose you originally have a 20 GB FAT-formatted hard drive with 10 GB used for 50000 files in 2000 directories.
You put a new OS of 2 GB on that drive.
# You lose 10% of all data on the drive (2 of 20 GB).
# You lose 20% of your data on the drive (2 of 10 GB).
# You lose 20% of your files that were allocated in the overwritten area.
# Because most of the directory entries are located in the first 2 GB you lose an additional 30% of your files. (You might be able to recover some of these files as "lost files", without file names.)
# You lose an additional 10% of all files due to fragmentation and overlapping between the two areas.
You will be able to recover just about 40% of your files undamaged. 10% will be partly recoverable and possibly half of the "lost files", 15% will be recovered without file name.
http://www.runtime.org/recoverability.htm
Klingt nicht gut <bigcry>