My work computer refused to boot one day, complaining of a corrupt dll. I replaced the dll from two different sources, but it still wouldn't boot. I had to re-install Windows, which was already a pain, because it meant I'd have to re-install all the programs as well -- that, or figure out a way to save the registry. (This is not normally an issue in Linux, although occasionally problems do get to the point that you need a "clean install.") My boss suggested reformatting the hard drive, so I had to re-install everything.
But that brought up a new issue: what about my files? I had quite a few programs that I had been working on. I hadn't checked in the source code into Subversion, and there were other files besides source code. I actually have two hard drives on my computer, so it would be trivial to copy the files off of the c: drive before I reformatted it. It would be trivial, that is, if only I could boot my computer. The Windows install cd gives an option to boot into DOS, but only a limited version of DOS: there is no xcopy command, and the copy command is not recursive. The only way to copy my files would be to do it one by one, and there were dozens to do. Surely someone had a regular Windows boot disk that I could use? Or someone could create one?
It turns out: no. No one had one, and no one knew how to create one. I tried. I went into all the Windows administrative tools that I knew, and I googled it, and I even went a ways toward creating a boot disk until I realized that it was actually just another install disk. In an office full of software developers and support specialists, no one could produce a cd that would boot into Windows. Fortunately, I had an Ubuntu LiveCD at home. I brought it back after lunch, booted up, copied my files from one hard drive to the other, and then did the Windows install -- all quite trivial, but impossible, in this case, without Linux.