How do I wipe my computer clean before donating/selling it?

I plan to donate two computers, but want to ensure that no one can find any of the data or other items I had on it.

I have a 1999 laptop (I can still boot it up, but the battery won't hold a charge) and a 2003 Dell computer that is running XP. I believe I've moved all the data (word filed, pictures, etc.) on my 2003 Dell computer to a new computer, so there is nothing on either the 1999 laptop or 2003 Dell computer that I want to keep.

I have the original system and other disks that came with both computers.

Thanks for your replies.

 

I believe dban is the program you're looking for http://pcsupport.about.com/od/data-destruction/fl/dban-dariks-boot-and-nuke-review.htm ...

 

Version 2.2.8 of DBAN that kench links you to may not run on the two computers because of their architecture. You'll need to locate version 1.0.7 of DBAN (in ISO format) and burn it to CD then boot from that CD.

DBAN defaults to three passes but you can select seven passes thus making any recovery of data from the drives impossible.

Be advised that it may take quite some time for the wiping to complete. It takes 19 hours and 43 minutes to wipe my 80GB drive with a single pass (I do this when I'm re-installing Windows).