How do I completely delete any and all information that is stored in a sony vaio laptop computer?

Passwords have been not a issue, viruses are. we do not caring what we remove we wish to remove everything. Please be specific as well as where to click or press come in as well as how most times to do it. Thank you

Suggestions:


1. Just use http://www.dban.org/ . Download the .iso, burn it to a disk, boot from it and follow instructions on the screen – default options are good enough.

2. just re-format the hardrive

3. simply reinstall windows