This should help: Guides for format and reinstall: http://www.geekpolice.net/tutorials-guides-f13/how-to-reformat-and-reinstall-your-operating-system-t15119.htm#95115

http://www.helpmyos.com/tutorials-software-alternatives-to-proprietary-f19/how-to-reformat-and-reinstall-your-operating-system-the-easy-way-t1307.htm#3143