Dumb but effective: overwrite all data
For Spinning disk drives, and SSD's that don't support secure erase/sanitize commands, the only other option is to manually overwrite all the data on the drive.
Windows:
Use the built-in format
command to erase drives. This takes a while and has NO FEEDBACK, so it's a "let it run until it's done" thing. This only works on drives that are NOT the boot drive. Steps:
- Using the disk manager, "quick format" the drive to have one single partition that spans the ENTIRE drive (with no space before or after the partition) and assign a drive letter and name (ex, drive K:)
- In a cmd window, run the command
format k: /X /P:1
[format drive k:, unmount before formatting, zero all sectors, then 1 pass of pseudorandom data]