First step to install Android X86 under your windows OS is download the Android X86 iso file and then download the virtual box here. Choose one which is compatible for your system, for example : android-x86-4.0-asus_laptop-20111209.iso. After downloading Virtualbox and the Android X86 iso file has finished, install it then created a new virtual machine, give it name whatever you want, choose Linux as operating system and Other Linux as version.
Uncheck to Boot Hard Disk
After that, we must set up the setting before install the android.
Go to setting >> System Tab then uncheck the Floppy Boot Order.
Click to enable PAE/NX on the Processor tab.
Browse Android iso file by clicking on the cd icon where located at right side. Click OK and start installing android X86.
Choose Live CD without installation, wait for a moment and enjoy your android X86. Don’t forget to press right ctrl + I for disable mouse integration. Now you can try an Android OS before you buy an Android mobile. 🙂