Arriving in the office today I got notice of a notebook that a customer brought in and it should be reinstalled. Unfortunately nobody can find an install CD that is matching the license key labeled to bottom of the notebook - neither the customer nor our technical staff.
...yes, it is a Windows installation. Variants of license keys must match the variant of CD used.
It is typical - especially for home users - that they do not find their (correct) install CDs when needed. Unfortunately many people are not well organized.
Similar things happen to different type of software pieces. For instance, I used the Wise Installation System software and we have bought an upgrade a long while ago. When I later reinstalled my development machine I first had to install the older version, enter the license key and then - you might guess - upgrade and enter the new update license key. I do not know if current versions are still made this way. When reinstalling a complete machine you can easily get in rage entering (typos included) serial numbers.
There was a time when I argued against software automatically connecting to the internet and automatically retrieving their license from the internet. But now I think this is maybe the less annoying variant. - However, we also have bought software in the past designed that way and often we had to argue that the old machine was replaced with a new one and that they can be sure there is still only one license used.
What companies do to ensure that people do legally use their product caused me to avoid commercial software wherever possible. And indeed even on my Windows machine at work I use mainly free and open source software. This is the best way from avoiding pain when reinstall is required.
Related posts: The Open Source movement, Paying for free and Open Source, The Open Source idea.