Newbie Question about clearing off a PC

[G-Diddy20]

I am making a purchase of a dell desktop and dual monitors for my poker playing. Previously I had just been playing on my laptop. i want to clear all the junk of my laptop now, poker rooms, videos, songs, pics, etc, and just start from scratch and use my laptop as my "photo center", music storage, videos etc..
what's the best and most efficient way to clear off all of this junk from my laptop so it will be "clean" and ready to go so to speak

G