How to Completely Erase a Hard Disk Drive

Hi
im plan to sell my compter i need to know How to Permanently Delete Data from the Hard Drive , i know in format can do it but some one told me data can be recovery easy my software
I need to know completely erase a hard disk data
Answer #1
Use DBAN
http://www.dban.org/
Answer #2
thx i will download now
Answer #3
Kill Disk always works well for me.
http://www.killdisk.com/
Answer #4
CCleaner also do it and do it nicely…
Answer #5
Depends on what kind of erase you want.
Wipe a HDD completely: (nothing no OS) Use DBAN
http://www.dban.org/
Want to erase cookies from browsers or some tmp folders try CCleaner:
http://www.piriform.com/ccleaner
Want to erase deleted disc space try Eraser
http://eraser.heidi.ie/
For commercial erase software try:
http://www.east-tec.com/consumer/eraser/
The above is for Windows for GNU/Linux files below
I use shred for my files better then most anything on Windows, can be found on most distros
There is also Wipe:
http://wipe.sourceforge.net/