How do i start fresh with linux??

Ive been experimenting with debian adding s/w changing configurations etc. I want to undo all that and start my beaglebone like when it was fresh out the box. How do i do that? also whats the term for doing this what do you call it???

"re-flash"

http://beagleboard.org/latest-images

Regards,

So all the files and software, etc. is stored on the eMMC chip on the BB? Does it take the role of the hard drive on a PC?

Sure.