reboot with cd in drive go into your bios(most computers are F2?) Change your boot options to cd first. Then F10 save and restart, then it should say press any key to boot, go ahead and hit any key. It will go through its auto run and load what ever it loads, then you will be asked what you want to do, your choices are Enter for new install or R for rescue. You want Enter new install then you will be faced with the terms of aggreements F8, then your partitions. As everyone else said make sure you delete all your partitions, i believe you hit D(delete) then it will ask you if your sure and i think L is the button just read lol.