Upgrading to pre-release windows 8

So a while a go I installed the windows 8 consumer preview, i put it on a separate partition and am dual booting windows 7 and windows 8 CP. I love win 7 and honestly am not sold on Win 8 yet, but i want to give it more chances. I wanted to upgrade to the latest version (pre-release?) I have the setup file on my Windows 8 desktop. I run it and it gets to the install part and I keep freaking out and backing out.

It never asks me what partition its installing on, I assume it will overwrite the windows 8 version of windows the setup is running on, but I don't want to lose my windows 7 and files if not. Someone please confirm that it will install on my win 8 partition and not my main windows 7 partition (C:\)