I installed VirtualBox 5.2 on an HP 540 laptop running Windows 10 Pro 64-bit.
But in VirtualBox, I can't find 64-bit option.
I didn't find any virtualization technology option in my BIOS setting. After that, I tried to import 32bit virtualbox image and here is an error that is Vt-x ; how to solve it.
According to HP documentations, HP 540 Notebook PC runs on one of the following:
None of them support hardware virtualization. That's why you didn't find any corresponding settings in BIOS.
So, it is not surprising at all that you cannot create 64-bit guest VMs.
Note for future readers: Given the HP 540 specs, "64-bit" here means "x64" not "ARM64". Also, the original poster appears to have discovered, as of this writing, VirtualBox requires hardware virtualization support to virtualize an x64 guest OS.
The guest OS inside the virtual machine hardware is determined by the settings chosen when creating the virtual machine. It is most likely that you selected a 32 bit guest when you created the VM.
Edit: According to https://www.virtualbox.org/manual/ch10.html#hwvirt
"VirtualBox's 64-bit guest support (added with version 2.0) and multiprocessing (SMP, added with version 3.0) both require hardware virtualization to be enabled." So based on EUserNameError's answer, that your CPU does NOT support hardware virtualisation, selecting a 64 bit guest OS will not be available to you.
