******** Update 11th January 2013 *********
It’s working now on Windows 8 RTM no need for any third party application.
******** End of Update *******************
I was stacked in how to open chm file on Windows 8, I read many posts about some registery option and disable UAC but nothing work 
So I start search for winhelp for Windows 8, but I couldn’t found it too
This maybe because I am working on Windows 8 CP and the other HDD has Windows 8 RP but it’s not stable on my Laptop (Dell XPS) specially with touch screen driver that still a beta with some error of course, so the following solution is just a temp for now, by the way if you want to have a look on Windows 8 on touch screen, see the this post
So finally I search for Ubuntu chm file so I found this wonderful application that makes me able to view chm file 
xCHM
