How do you clear out your computer?

Im donating my computer because I got a new windows vista equipped one. The only thing is i don't know how to get rid of all my stuff off of it, like programs, documents, and all that mumbo jumbo that is stored deeep within the computer. How do i clear the computer completely?How do you clear out your computer?
if you have the restore discs, choosing the reformat options will work , if you don't have restore discs you can borrow a windows 98 startup disc and reformat it with the Format C: options and donate it wiped clean. if you are worried about the prior programs having sensitive data then the best thing is to use a disc washing program.How do you clear out your computer?
When you reformat the hard drive choose the option to zero it out, , It will take a good long time, more so the larger capacity it is and low RPMs.
Try Eraser 5.7 Though this software is free, a $15.00 donation is encouraged. This software does a great job of sanitizing your hard drive by removing all magnetic and solid state memory. It does this by using several different techniques including ';pseudorandom data overwrite'; and techniques defined by the Department of Defense.


http://www.heidi.ie/eraser/
If you have the recovery discs that came with yur computer put disk 1 in chose';format'; option and follow the instructions. You compuer will be just like the day you got it.