How do you clear everything off a Mac as if it were new?

How do i restart and delete absolutely everything at all from my macbook ? Like if it was a new computer? The problem is that i bought the computer used and there is no way of changing the owners name i tried changing my user as Admin but it doesn't...

I'm fine with using Disk Utility, it's just what do I erase to get EVERYTHING gone from my mac? It's really slow and I have all my stuff from previous years (which I doubt i'll need). Here are my options of what to delete: 232.9 GB WDC WD2500J austin...

I want to know how to delete everything, such as everything and anything ever done on the web or looked at absolutely everything so nothing ever done can be looked at by a smart computer person trying to find out anything that ive been on ever.. How...

Help! i dont know how to backup everything through time machine.. I tried opening the time machine (in system preferences) and turning it on... then it says to choose the disk you want to use for backup.. there were no disks! i was confused... do i need...

i want to delete all photos everything! im selling my macbook pro so everything has to go. oh and i lost the discs and stuff..all i really have is my computer :( oh and how do i delete my yahoo account ?

I just got a computer from my sister it's a mac bookpro 2008 13''. I want to remove all of her things off of it and reset it to where it's like a brand new computer, ...show more

My two year old brother got on the computer when i left it for a couple of minutes and when i came back the screen was zoomed in on everything and when i moved the mouse the screen moved with it. i have tried everything i know but it wont go back to...

I just recently bought a used iMac computer, and i want to completely erase everything the original owner has on here. How do i do this?

I put a kodak easyshare instalation CD in so that i could install the kodak program to upload pictures. it went though the installation procedure and then told me that i needed to restart my mac. so i clicked restart.i left for like 5 minutes and came...