I kinda wanted to erase everything on my Imac, and start from the beginning. Anyone know how to do this. And I have Lion on it, so hopefully I won't lose it, I am assuming I can back it up?
You seem to be asking about erasing everything on your computer and reinstalling all the software; you'd also lose all your settings and any documents and files you created. Is that what you "kinda" want to do?
I would recommend you first look into how to backup your computer via Time Machine or Super Duper or Carbon Copy Cloner. That's a required first step unless you want to lose everything you've created.
Maybe you just need to do a little tidying up. I see no reason to erase your hard drive. OSX has built in optimization so just toss and or save what you don't want on the hard drive and then do a restart.
Disk utility is a software program that's on your mac. You can launch it from the recovery area in Lion as explained in previous post, or you can launch it when booted in Applications>Utility's>Disk Utility
I think you would be better off stating the problem you think you would solve by 'kinda' wanting to erase your disks and starting over. Then, perhaps people could suggest less drastic 'solutions' to the real issue.