Hyper-V as many people know is available with Windows 2008. You can also get a version of Windows 2008 without Hyper-V. I suspect this is due to trying to avoid any anti-trust issues. Anyways, the Hyper-V component is available in both 32 bit and 64 bit versions of Windows 2008. This is where the confusion comes in. If one doesn’t read the available documentation clearly, one would assume that Hyper-V works in both 32 bit and 64 bit 2008, but then that person would be wrong. You see the tools available to manage Hyper-V are available in both 32 bit and 64 bit Windows 2008, however you can only run Hyper-V on a Windows 2008 64 bit box. If you were to try and do this in a 32 bit environment it just would not work.
You can however run a guest os (a guest os is an operating system you run inside a virtual machine) in 32 bit mode inside of Hyper-V. If you want to run a 64 bit guest os you can do that as well. So if you want to build a cheap test box for yourself then you will have to buy a 64 bit processor and build a workstation for yourself and install Hyper-V on that. There will be no reusing of an old 32 bit system to run a Hyper-V test box.
If you do want to virtualize in a 32 bit environment I suggest you check out VMWare, you can easily do it with any of the VMWare products. Until next blog, have fun virtualizing!