Acer Veriton Z2640G - Manual (Page 29)

Acer ProShield - 29
Data Removal
Here you can select files to be completely removed from the hard
disk. The File Shredder overwrites the data to make recovering the
data impossible.
Warning
Make sure you select only the information you want to shred. Once you
have shredded a file or folder, it is impossible to recover the data.