Can I run Windows 7 on a portable hard drive that I can use on multiple computers? In the old days I had a hard drive enclosure that let me slide a hard drive into different computer. From the reading I have done so far, it does not look like Microsoft is allowing that. It looks like the OS is now tied to the motherboard/cpu configuration. My son and I are building computers for fun and I would rather not have to purchase a new copy of Windows 7 every time we build a computer. It adds $100 to the cost. If that is the case I guess we could run Linux Ubuntu for free.