Most Linux Live CDs can do it but it is not for the faint of heart!
There are really simple tools that will wipe drives.
This one is the easiest.
Instead of using the gparted interface just open the terminal and issue the command.
sudo dd if=/dev/urandom of=/dev/sda1
Hit enter and wait because it will take quite a while. What this does is use a simple device
dd (a link to a wiki page about how it works) (which is a core program) to write random numbers to the entire harddrive except for the boot sector.
This is if you only have one partition on the drive...which is usually the case with Windows installs.
Also you might need to stop your swap and unmount the drive if you use some other live cd.
This is done from the terminal with the commands.
sudo swapoff
and
sudo umount /dev/sda1
gparted can now unmount for you
so I doubt this is necessary anymore.
I haven't had to nuke drives for people in a long time so I am a bit old school and out of touch, but I know my commands!
If however you have multiple partitions or there is a weird ibm, dell or whatever recovery partition on the 'puter you want to keep, then to see which one is the recovery (if any) just use gparted to discover the correct names and sizes of the partitions.
Then you can just nuke the correct one(s), if sda1 is something other than the system and data. You never know you might have windows and the data on something strange like sda5...
IF YOU issue the command:
sudo dd if=/dev/urandom of=/dev/sda
Then all bets are off and everything on the drive will get wiped including the boot sector. So this is the h-bomb of nuke commands!
It is one of the commands that you do not use on your system unless you know what you are doing, because it will wipe it completely. If you try it make sure there are no issues with the drive as this will kill it if it has overheat trouble... also make sure that there is adequate air circulation and your case fan is working! It can take over several hours to complete on really large drives and spins them up big time for the entire duration.
Essentially you nuke the drive by writing data to every sector so it can take quite a while to accomplish depending on the size of the drive and the speed of the system bus.
The other option is to do a full system reformat which takes much less time.
If you just do a full system format to a weird file system like ext3 then most likely it will wind up getting NTFS put right back on it.
So if you sell or give the computer to someone that is going to just put XP on it because it has a sticker (which is usually the case) then most "windows techs" that use XP do not have the skill to see what was previously on a drive before a full Linux format.
Heck just put a copy of Mint Linux on it without windowsXP getting in the way you might just wind up keeping it!
So don't sweat it.
