How do I get Android-x86 (32-bit or 64-bit) non-UEFI to boot in VirtualBox? EDIT: I'm getting similar results in both 32-bit and 64-bit.

Summary

I am installing Android-x86 version 7.1 32-bit or 64-bit in VirtualBox.

If I install it using UEFI (64-bit only), it works, but I cannot resize the screen, a problem to which I have been unable to find an answer.

Therefore, I need to install it without UEFI, so that I can resize the screen.

Problem

The Android installation runs smoothly. But, no matter what I have tried, once installed, the non-UEFI Android system won't boot.

If I use a GPT hard disk, I get this error message when booting the newly-installed Android, whether 32-bit or 64-bit:

FATAL: No bootable medium found! System halted.


If I use an MBR hard disk, I get this error message when booting the newly-installed Android 64-bit:

  Trusted GRUB now booting command list

  Progress:
Error 15: File not found

tGRUB: ******************************************
tGRUB: * An error occured which might result in *
tGRUB: * an unverifiable or insecure system     *
tGRUB: * state. !!! BOOTING WILL BE STOPPED !!! *
tGRUB: ******************************************


And the 32-bit starts with 100% CPU and goes nowhere (very fast!).

More information

Host


Linux Ubuntu version 16.04 64-bit
VirtualBox version 5.1.28


Guest


Type Linux, Version "Linux 2.6 / 3.x / 4.x" (32-bit or 64-bit as appropriate)
System Base Memory 2,048 Mb
System EFI turned off
Storage


Controller: IDE for the optical drive to hold the Android-86 ISO
Controller: SATA for a 40 Gb hard disk



Question

How can I get Android-x86 to boot on a non-UEFI system on VirtualBox, please?
When you try to install Android x86 on pc HDD, try to provide a boot partition through Create/modify partition and make it bootable. Followed by that create a new partition as Linux. write both the partition and after that install the android x86 on the linux partition (formatting as ext4). 

It will work, after allocating a bootable partition. I tried and it worked.