If you don't want to burn it to a disk, download 7-Zip (despite the name, and what you're trying to do, it has nothing to do with Windows 7), and then extract the ISO to a folder on your desktop. Then when it's all done extracting, open the folder, and hit setup.exe, and this will start up the upgrade process. It will usually take longer, but i think it's worth saving a disk for something else....like bootlegging Full Albums off of mininova... I mean... i didn't say anything...