lala wrote:the problem is that i have made a format to my pc lately.and i didn't save the data from it.
A data recovery software will still be able to retrieve the data.
It takes several full formats as well as full "write zero" passes in order to fully erase data on an HDD.
To fully erase data on an HDD, you will need to perform:
1. Fully format the HDD.
2. Completely fill the whole surface of the HDD with zeroes (write zeroes) with a software such as Western Digital LifeGuard Diagnostics (1).
3. Fully format the HDD (2).
4. Completely fill the whole surface of the HDD with zeroes (write zeroes) with a software such as Western Digital LifeGuard Diagnostics (2).
5. Fully format the HDD (3).
6. Completely fill the whole surface of the HDD with zeroes (write zeroes) with a software such as Western Digital LifeGuard Diagnostics. (3)
7. Fully format the HDD (4).
8 . Completely fill the whole surface of the HDD with zeroes (write zeroes) with a software such as Western Digital LifeGuard Diagnostics. (4)
This procedure is also explained in the US Govt document DoD 5220.22-M Data Wipe Method [US DOD Wipe Standard].
If you have only formatted your hard drive only once, 99.9% of your old data is still in there and can be easily retrieved.