VirtualBox - Select 32-bit or 64-bit guest CPU, Windows 7 32-bit installer hangs on startup

Select 32-bit or 64-bit guest CPU

The selection between 32-bit and 64-bit is done using the following setting in the machine settings:

General, Basic, Version

This option that may seem to only set the OS title for the description actually switches a setting inside the .vbox file defining the machine settings inside the following tags:

VirtualBox, Machine, Hardware, CPU, LongMode = false is 32-bit, true is 64-bit

Windows 7 32-bit installer hangs on startup

If you have created a 32-bit machine and find that a Windows 7 32-bit installer disk hangs on startup, ensure that the following items are checked in the machine settings:

System, Motherboard, Enable I/O APIC
System, Processor, Enable PAE/NX - Note, this also applies even if you have less than 4 GB RAM set on the guest machine for some reason.