After trying to mirror my harddisk with Norton Ghost, the damned tool
mirrored the wrong way.
Now the last 12GB of my 27GB hpfs partition are all 0xFF. Don't ask

A check with dfsee tells me that there are thousands of errors
"allocation set, but not in FS-administration" or "in FS
administration, but allocation not set".

Should I run CHKDSK /F or are there better ways to recover?