The current link to download Microsoft Software is here for faculty and staff. For University of Colorado Boulder students and faculty, you have access to various versions of Windows software for free online. Obtain a copy of the operating system you want to install.For example, if you are sitting at a Windows machine, make sure to download VirtualBox for Windows. Be careful when you are downloading VirtualBox: select the proper “host” computer. The computer that you are actually sitting and working on is the “host” computer, whereas the computer you will set up later will be called the “virtual” computer. Essentially, this program sets up an entire new “virtual” computer within your computer, so you can install different operating systems, etc. VirtualBox is free, and seems to work well with what we’re doing, but note that there are also other virtual machines as well. Download VirtualBox which is the virtual machine software. For example, a collaborator of mine uses the EPA Water Treatment Plant model which only seems to work under 32-bit versions of the operating system. In this post, I’ll talk about how to set up a virtual machine on a PC, in order to run outdated software that may have been optimized for a different version of Windows.