Installing Windows XP maybe bit tricky in Asus K40IJ Notebook laptop.
If you already tried you may get a error during the installation process. That is because XP cannot detect the SATA hard drive in K40IJ.
First goto bios by pressing F2 when the machine boot up.
Then goto Advanced -> IDE Configuration -> SATA Operation Mode -> default is Enhanced (Compatible/Enhanced) -> Change to Compatible.
Then you can install XP without a problem.
But this method will slow down your laptop.
You can find more useful info here
Subscribe to my blog