Files Erased, but still available?

[basics]

I am using Eraser 5.6 under XP Pro

When I Erase 'unused space'o n a drive or 'Erase recycle bin' ( passes 7times) I still can find this files and all names/ sizes of the files with any recovery program... ( as Pc Inspector/-r-undelete )

I have to say that actually recover the files doesn't work, but I am very surprised of this...
I guess you don't may find these files back , isn't it?
Now I wonder if anyone could open this files again , maybe with specialized programs..

 

[basics]

Does 'erase unused disk space' overwrite all in previously( in history) deleted files wich have not been erased with'erase recycle bin' ?

Let me say: If you don't 'erase the recycle bin' , could you then later on 'erase unused disk space'?

 

[basics]

Is there nobody who knows??