So I downloaded the Microsoft Longhorn Beta 1 ISO from my MSDN account. There were two possibilies for me testing Longhorn on VirtualPC on my Laptop: burning the ISO images to a DVD or using a virtual CD-ROM drive that can mount ISO images. See even though VirtualPC can mount ISO images, it is unable to mount DVD ISO images because it thinks they are too big. (I sure wish Microsoft would fix VirtualPC.) My preference went to mounting the ISO somehow, so I decided to Google for a solution. Microsoft seems to have an unsupported “Virtual CD-ROM Control Panel for Windows XP“. It is very simplistic, but it works like a charm on my XP SP2 machine, and as I write this I am installing Longhorn in to VirtualPC.