Recently a few guys in my team were using a tool known as VMWare for simulating different operating systems on a single machine. Here's some info on how this is done:
VMWare hosts each guest operating system in a separate, secure virtual machine. Each virtual machine (VM) has its own virtual CPU, memory, disk, etc. and all of the virtual hardware is mapped to your computer's real hardware. Each virtual machine also comes complete with its own BIOS that can be edited the same way you'd edit the real BIOS on the computer that VMWare is running on. This lets you customize your virtual machines and control all of the usual stuff that you can control via your PC's actual BIOS.