Here's your step by step guide to erasing all your data off a Mac and re-setting it to a clean factory install of Lion.

I've got an old mid 2007 MacBook that I've been using as a media server but with my recent purchase of the new Retina MacBook Pro, my old Macbook Pro will now take it's place and it's time for me to pass on the Macbook to a new home.

The first step is to do a clean install of the OS but I soon discovered this isn't as straight forward as when you had a DVD to install from.

Lion is a totally (pardon the pun) different beast. It was Apple's first release of an OS through their App Store. As such it's not as straight forward to reformat your drive with a clean install.

Be warned - Doing the following will ERASE ALL YOUR DATA  !!

Step 1 - Reboot your machine holding down CMD + R

Step 2 - Choose the Disk Utility Option

Step 3 - Choose Macintosh HD and click Erase.

Step 4 - Close Disk Utility

Step 5 - Choose Reinstall Lion

That's it! Hard to believe it took me 2 days to figure it out. The problem I had was that I made the presumption that choosing "Reinstall Lion" would indeed reset my Mac back to factory. It doesn't though, it keeps all your account info and Apps.

You'll need either an ethernet or wireless connection and your Apple ID credentials.

Your Mac is now all set to be put up on eBay for a new home!