I plan to sell a laptop and a desktop PC. I will be sanitizing both hard disks. I hate to ask a dumb question, but after a hard disk is completely erased and a computer is then restarted, what does it boot to--a computer's BIOS setup menu? Something else? I've obviously never done this before--just curious.
If someone was really interested to find out what used to be on that drive, they would need just a set of forensic tools. I would personally replace the hard drive with a brand new SSD and take the old one and destroy it, due to the drive actually keeps the last gig accessed on a small circuit board that contains memory. I always take my hard drives that have been pulled and destroy them in a nice funeral by 5 pound mini-sledge and fire.
+1 for destroying that drive since deleted data can be recovered.
as long as you have nothing illegal, immoral, or fattening on it, or stuff you wouldn't want your significant other to see, and don't want to go thru the expense of a new drive, and the IRS is not after you, booting from a CD/DVD drive with a disk wiping program that writes random data multiple times to the disk should be sufficient. forensic data recovery is expensive and if you are a normal person with nothing to hide, and a bank account like most with not enough in it, that should be enough. if you feel someone really is out to get you, as it would be worth their while, then replace the drive with a new cheap ssd & mangle the drive with an axe then burn it. feed the remains to a convenient alligator or shark. you will feel better. even paranoids have enemies., but remember ISPs and 'cloud' thingamies may have a lot of info on you 'out there' and discoverable forever...anything on faceplant or twatter is immortal.
as noted it just won't boot after and you may get a message about the boot drive being not found, or offering to boot from a cd/dvd drive. there will be a key to press during powerup to get into the bios, which may have been password protected (the mfg. usually can supply a backdoor password to let you in if you forgot it, but you'll have to convince them it's really yours.)
you may want to reinstall an OS on top of it if you retain the drive after wiping it, to further obfuscate things. run 'privazer' on it and then uninstall/delete it. and don't connect it to the interweb...
and ask your analyst for help.
A simple format, even when re-partitioning disk, would allow for relatively simple data retrieval. For a normal user Download Active@ KillDisk - MajorGeeks should be quite enough because any publicly available forensic program wouldn't be able to retrieve anything from disk. One step further would be to encrypt disk before using kill disk.
None of normal data retrieval can retrieve everything with high degree of certainty so even if something is retrieved it would be practically useless as encryption keys would be lost in the process.
Five hard disk cleaning and erasing tools - TechRepublic
Of course the best secure way remains to smash it & destroy it as much as possible.
Quote
