How to make sure all data is erased on a computer hard drive
If your concerned with data being read or recovered from your hard drive after it has sold or given away, we recommend trying the following utilities. These utilities will remove all your existing data and make it impossible to be recovered or read. After your data has been erased or overwritten, you can then reinstall Windows or another operating system on the computer.
Warning: If you have an OEM computer (e.g., Acer, Dell, Hewlett Packard, etc.), the hard drive may have a hidden system recovery partition. Using the utilities below may erase this partition, making it impossible to restore your computer without a disc.
|DBAN (Darik's Boot and Nuke)||https://dban.org/||Free|
|Blancco||https://www.blancco.com/||Free and commercial version|
|Eraser||http://www.tolvanen.com/eraser/||Free to all|
|Harddisk Eraser||http://www.linux-kurser.dk/secure_harddisk_eraser.html||Free to all|
|Permanent Erasure||http://www.winhex.com/security/index-m.html||Free to all|
|SDelete||https://technet.microsoft.com/en-us/sysinternals/sdelete||Free to all|