I have a copy of Vista Business upgrade via the MS Action Pack. It does not allow you to install itself clean: you *must* upgrade an existing OS. In build 3120, I tried the following: Clean install of XP w/ SP1 in a vista VM. Hangs at installing devices. Clean install of XP w/ SP1 in a XP VM. Installs fine. Unfortunately, Vista won't upgrade it, saying that ACPI is not enabled. Changing the settings in the VM from XP to Vista doesn't enable the upgrade to proceed either. Any workarounds for this? I'd rate this one critical.. Alan.