How to run Android-x86 5.1 Lollipop with VirtualBox

Android-x86 is a project that ports Android to x86 platforms that allows us install and run Android on the PC. The latest stable release prebuilt image is Android 5.1.1 Lollipop favors. With more new improvement comparing to the Android 4.4 Kitkat, the Lollipop's worth mentioning key features are:

Supports 64-bit kernel and userspace, as well as 32-bit system.
Update kernel to 4.0.9.
Enable OpenGL ES hardware acceleration for Intel/AMD(radeon/radeonsi)/Nvidia(nouveau) chipsets.
Support booting from UEFI and installing to UEFI disk.
Be able to install to ext4/ext3/ext2/ntfs/fat32 filesystems via a text based GUI installer.
Support Multi-touch, Audio, Wifi, Bluetooth, Sensors, Camera and Ethernet (DHCP only).
Auto-mount external usb drive and sdcard with filesystem vfat/ntfs/exfat/ext4.
Support VM including Qemu, VirtualBox and VMware.
Support foreign archs (arm / arm64) via the native bridge mechanism. (Settings -> Apps Compatibility)

The Android-x86 Lollipop may still buggy on x86 platforms. Running it as a virtual machine would be a wiser choice, instead of installing along with Windows permanently on hard drive.

Things you need:

Download and install VirtualBox.
Download ISO image of Android 5.1 Lollipop.

Steps:

Open VirtualBox, click New.

Create Virtual Machine for Android. Choose Linux for type, Linux 2.6 / 3.x / 4.x (32-bit) for version.

Set memory size (RAM) to be allocated to Android VM. Recommended RAM size would be at least 512MB and above.

Create virtual hard disk.

Select VDI (VirtualBox Disk Image)

You can choose either Dynamically allocated or Fixed size.

If you choose Fixed size, set the size of virtual hard disk for Android VM then click Create.

Open the settings of Android and go to Storage tab. Load the downloaded Android ISO image into virtual optical drive.

Start the Android VM.

Select Installation - Install Android-x86 to hardisk.

Select Create/Modify partitions.

Choose No when asked to use GPT.

Select New to create new partition from free space.

Select Primary to create a new primary partition.

Select Bootable.

Select Write to write partition table to disk.

Type yes to confirm.

Select Quit.

Select the partition that just created to install Android-x86. Eg. sda1

Select ext4 filesystem to format.

Select Yes to confirm.

Select Yes to install boot loader GRUB.

Skip not to install EFI GRUB2.

Select Yes to install /system directory as read-write.

Wait for the installation to complete and done.

Remove the ISO of Android from virtual optical drive (Devices > Optical Drives > Remove disk from virtual drive). Then reboot the Android VM.

Select Android-x86 5.1-rc1.

You will see the Welcome page of Android. The Android 5.1 Lollipop live and running on VirtualBox.

The one last configuration you may need to do is go to Input and select Mouse Integration to have better control of the cursor on the Android VM's user interface.