I have tried to erase and overwritten(ccleaner 7 passes)a 20GB old hard drive, however, 90MB are still used -according "properties". I have activated(folder properties) "show hidden system folders", and the only one which appearing is Recycle Bin( around 4MB).No other. Is this a Restore point, or might be the disc is not correctly erased?
If it is a Restore point, how could I totally erase these near 100MB? thank you very much.  

- williamsonn

I have tried to erase and overwritten(ccleaner 7 passes)a 20GB old hard drive, however, 90MB are still used -according "properties". I have activated(folder properties) "show hidden system folders", and the only one which appearing is Recycle Bin( around 4MB).No other. Is this a Restore point, or might be the disc is not correctly erased?
If it is a Restore point, how could I totally erase these near 100MB? thank you very much.

Well, if you have a recycle Bin on it, you also have a filesystem on it, and the filesystem structures do (obviously) occupy some space.
Try opening that disk in (example) DMDE:
softdm.com/
and you will see....
And of course overwriting/wiping with more than a single pass is completely UNneeded.

jaclaz
_________________
- In theory there is no difference between theory and practice, but in practice there is. - 

Do a Full format with Windows 7 (or Vista) This will wipe the disk (once, which as jaclaz says is all you need). It will then add the file system.

If you use FAT32 it will be clear where the file system sectors are stored, FAT and root directory only.
_________________
Michael Cotgrove
www.cnwrecovery.com
cnwrecovery.blogspot.com/ 

- mscotgrove

Do a Full format with Windows 7 (or Vista) This will wipe the disk (once, which as jaclaz says is all you need). It will then add the file system.

If you use FAT32 it will be clear where the file system sectors are stored, FAT and root directory only.

... and you will have again some space occupied by the filesystem.

If you want a "completely empty" disk, you must not partition/format it, i.e. have NO filesystems on the disk - or if you prefer you add nothing to it (but then how exactly will you access it to see if it is empty)?


jaclaz
_________________
- In theory there is no difference between theory and practice, but in practice there is. - 

I have been using these mentiones harddrives for storing some music and then I have been again thinking on the same question. You mentiones that the occupied space was due to the filesystem: required for the drive works properly, now, I wonder this:

1-Are not the mentioned space(around 100MB for a 20GB hard disc)excessive for a filesystem?

2-If you erase totally overwritting a hard drive, 1 pass, What happens with the space occupied by the filesystem: is it also overwritten before being again occupied by those archives?

thanks  

By th way:, now, despite the "show hidden folders" option is activated I can,t see not even the recycle bin.  

What are the HDD specs (Make/Model)?

When you say "erase," do you mean the file system, the partition, or the whole HDD?

If you are trying to erase the whole HDD, boot from a linux CD and use "dd" as in the following link:

How to erase a hard disk