Dell publishes disassembling manuals. Unfortunately ASUS doesn't. I decided to show you how to solve overheating problem, or add additional HDD to your ASUS k72 series.
WARNING: You use this guide at your own risk. Disassembling notebook may result in loss of warranty. If you are not familiar with such things, don't do it. Author is not responsible for any harms, and losses that may occur during operations described here.
Firstly I advise you to sort screws.
1. Remove battery and unscrew four screws, which you can see after that.
2. Unscrew two screws - colored blue on photo below and move out CD recorder. Unscrew four screws, which you can see after that.
3. Unscrew four screws from cover (red on photo), and take off the cover
4. Unscrew all screws colored green
After opening cover:
1. Unscrew four screws (red) that hold your HDD.
2. Carefully pull the drive.
3. Unscrew five screws colored blue on picture below.
Use something to lever up keyboard (I used guitar pick).
Next you have to do is to pull off the lock and move the ribbon.
Remove all 6 screws.
Again you have to move lock and remove the ribbon (smaller one).
Use a guitar pick or sth. like this to pull out the upper case. Do it CAREFULLY. The worst part is placed near screen.
To remove fan unscrew two screws on it, and peel off the ribbon. Remove fan.
Use a vacuum cleaner to clean radiator.
To change HDD position just put it on second socket, but check if you need some casing for it.
If You'd like to change the thermally conductive paste on GPU or CPU, You have to remove screws with triangle symbol (on image colored green) and gently lift the mainboard (starting with left side) plug-out LCD and Wi-Fi ribbons. You are ready to remove mainboard from the casing.