What do you do with customers who don't have or can't find product keys for Windows, Office, etc.? I find the majority of   people who ask me for help fall into this category. Unless they have a laptop with the product key stuck underneath, they rarely can find their original product keys. I'm then faced with telling them they need to shell out hundreds of dollars or switch to Linux. Some of the them switched, but unless they're willing to learn Linux, that's a whole new set of problems (e.g. they call you saying "I downloaded MSN but I can't install for some reason").