ASUS doesn't provide recovery disks, as of October 2015, but you can create your own recovery disk using apps such as Backtracker and Easy Recovery Essentials. However, if you installed the operating system yourself, you aren't able to recover using Backtracker.
Backtracker is only compatible with laptops running Windows 8 or Windows 8.1. To download the setup file, go to the official ASUS website, search for it, click Drivers & Tools, and select the version of your operating system.
Easy Recovery Essentials is compatible with Windows XP, Vista, 7, 8 and 8.1. Its setup file is available on NeoSmart.net. In addition to the recovery utility, it comes with advanced tools for experts and a built-in antivirus.