How to properly wipe files off a hard drive?

[10ftcoke]

If you overwrite a file and disable windows shadow copy (system restore) service, is there anyway to recover the overwrited files?
I've heard of people recovering data from wiped hard drive disks. Any guess as to how they do it?
I'm need to know because I accidentally erased a text file that had all of my passwords stored on it...

 

[Infinite]

To recover Data:

http://www.piriform.com/recuva

To clean a Hard Drive:

http://www.sevenforums.com/tutorials/52129-disk-clean-clean-all-diskpart-command.html

Do the Clean All.

 

[search53]

Yes, it is possible to recover files from almost any hard drive, no matter what method you use to wipe it. It does quickly become rather time consuming and requires expensive equipment... but it can be done.

It involves examining the hysteresis history of each "bit" on the hard drive. Long story short, the precise amount of magnetism on the platter is measured. The amount of magnetism of a "0" that was once a "1" will be different than a "0" that was always a "0". A "1" that was once a "0" will be different than a "1" that was always a "1". This is an oversimplification, but it illustrates the concept behind the analysis.

 

[Corazon]

That's a good explanation but only applies to data that was actually wiped rather than just deleted.

May I suggest that the OP keep a backup of this text file...and consider encrypting it too, it's kind of risky to just have all your passwords floating around in a plain text file that anyone could access.