To do with hardware changes in XP and the tolerance to reactivate...
"How does product activation determine tolerance? In other words, how many components of the PC must change before I am required to reactivate?
Common changes to hardware such as upgrading a video card, adding a second hard disk drive, adding RAM or upgrading a CD-ROM device will not require the system to be reactivated.
Specifically, product activation determines tolerance through a voting mechanism. There are 10 hardware characteristics used in creating the hardware hash. Each characteristic is worth one vote, except the network card which is worth three votes. When thinking of tolerance, it's easiest to think about what has not changed instead of what has changed. When the current hardware hash is compared to the original hardware hash, there must be 7 or more matching points for the two hardware hashes to be considered in tolerance. If the network card is the same, then only 4 additional characteristics must match (because the network card is worth 3, for a total of 7). If the network card is not the same, then a total of 7 characteristics other than the network card must be the same. If the device is a laptop (specifically a dockable device), additional tolerance is allotted and there need be only 4 or more matching points. Therefore, if the device is dockable and the network card is the same, only one other characteristic must be the same for a total vote of 4. If the device is dockable and the network card is not the same, then a total of 4 characteristics other than the network card must be the same."
Is there a problem, Powerless? These explanations can seem confusing at first sight, but in fact this one's pretty clear if you follow it through.
I've spoken to Microsoft in the past about plain English, and its value in communicating with customers. They take the view that it's better to use 'lawyer language' (for want of a better phrase) than to risk the terms being misinterpreted. In most cases they do a reasonable job, although you do need to concentrate pretty hard at times.