DBAN is your friend
Search for DBAN on Sourceforge, a solution which will completely erase your hard disk.
Otherwise you need something like eraser to wipe out free space on your windows disk.
As a Dad I'm pretty concerned about having my family's private information stolen. I'm also about to sell the family PC, which has loads of personal files on, like Excel/Word docs, saved bookmarks to my online accounts, etc. I've deleted all these, but a friend told me they aren't really gone and could be recovered with the use …
Hi, try the following URL (http://www.oo-software.com/home/en/products/oosafeerase/).
Qoute: "O&O SafeErase 3 is THE solution for the secure deletion of sensitive data from your hard disk and offers you the ultimate protection of your private sphere. With just one click of the mouse you can securely and permanently delete files, folders and partitions.
The motives for the deletion of files are many".
I liek O&O so download trial version (not sure what teh limits are for trial but it will tell you when you use it).
The only way you can be sure is to give them a fresh HD or no HD at all. It is possible to recover upto 32 layers of deleted data if you have the right tools but you have to ask yourself what kind of damage could actually be done with the information on there. Personally if I were you I'd probably just format and reinstall windows
Don't bother with any of those crazy bought solutions. Simply avail yourself of a Linux bootdisk distribution (such as Tom's Root Boot for a floppy, or knoppix for a CD). After booting up the floppy/CD and logging in, type:
dd if=/dev/zero of=/dev/hda
and wait until it finishes. Replace hda with sda for SATA disks.
The contents will, in my opinion, be erased sufficiently well as to be effectively unrecoverable by most people likely to come across your old computer.
Repartition and reinstall an OS if you choose to.