Richard writes: Wrong. As long as you have the certificate of authenticity for copies of MS-DOS, you can continue to ship product using that operating system. Medical device manufacturers are doing this because if they change the operating system, they have to requalify their devices which is a very expensive process. So they continue to buy NOS copies of MS-DOS, as long as they have the certificate of authenticity, and use those to ship their products. They will continue to do this as long as the cost of obtaining NOS MS-DOS product is less than the recertification process. Given the number of NOS copies still in the marketplace, they won't need to upgrade the OS for some time. There is a local guy who mostly deals in C=64 equipment that has been making quite a nice side business of finding NOS copies of MS-DOS for some time now. You would think so, wouldn't you, but as I said before Microsoft is being very creative. The software that you're talking about is unused, possibly retail or possibly OEM, but in any case the license has not been attached so it can be used on any device (for OEM, provided that the equipment is new). You would think that an OEM license, since it is attached permanently to the hardware, would transfer with the hardware, right? You would think that presenting the certificate of authenticity or other evidence that the hardware was licensed would be enough to show a license, right? Not so fast. A couple of years ago MS, upon a closer reading of the license agreement, noted the part that says that all copies must be transferred when the license transfers. Most people understood (and probably understand) this to mean that you can't keep any copies because there's only one license, but MS reinterpreted it to mean that if all copies are not transferred then it is not a valid license transfer and the license is invalidated, requiring a new license transfer. They set up a new "Refurbisher Program," whereby people selling used computers can give Microsoft more money to make sure nothing bad happens to their nice business. In an interesting twist, the now "meaningless" original "Certificate of Authenticity" must still be present, otherwise you need to cough up the full retail price should you want Windows - thus, per MS, the computer product the license is tied to is the mainboard (which cannot be replaced unless in cases of failure, when MS may choose to make an exemption if they really feel like it), the COA, and any manufacturer provided backup media, including the "recovery partition" of a disk which, if it is damaged, now appears to nuke your license for Windows. At this point they only seem to be targeting used computer stores selling machines with Windows, but until someone takes them to court and wins it could be anyone they want to squeeze. As noted, one copy of MS-DOS is probably not going to be a big deal, but MS appears to not be taking the "live and let live -after all we've already been paid" attitude and it might get worse. I found all of this out because of the good part of the program - MS will give really cheap upgrade licenses to qualifying nonprofits using used computers through the same program. Want to check it out? Search MS for "refurbisher program"