@Tzael

The reason people need to "hack" upgrades to do a clean install is that on an OEM PC, you have NO older copy of windows to inser when booting from the upgrade media, since you got only a restore disk, not a full media (unless you explicitly requested and paid extra for it post-sale).

Take a Dell you want to upgrade to 7, but you don;t want all the crapware and bloat you had before, since you have no medai with which to validate your upgrade copy, you either need to hack it, buy the full version, or pay dell for an authentic MS DVD of your OS.

Microsoft's complaint is that people are hacking the upgrade to install on a NEW PC by claiming they're upgrading the copy of their OEM installed on an older PC. OEM copies are NOT transferable. In fact, even your FULL copies are only transferable a limited number of times (for the original Vista release, it was ONCE, but Microsoft later revised that I believe to 3 times. Upgrades to not increase this number either... If your copy of XP had 3 migrations, and you had it on an original machine, moved it to another later, then upgraded to vista while moving to a 3rd, you can move 1 more time to a 4th box while upgrading to 7, but that's it, no more moves (legally speaking).

Keep in mind, "moving" to a new PC involves anytime you have replaced 3 or more core serielaized components as part of an upgrade or major repair (CPU, Moterhboard, GPU, hard disk, and network adapter, so changing a board with onboard video and NIC alone counts as a new PC unless you replaced it with the same model number board.). It does not matter if the component replacements are over an extended period either. Microsoft's technology looks for replaced components between a reboot, and you can fool this by changing parts over several days, however, the LICENS is bound not to the chassis, but to the SUM of the 5 core components, and if over time any 3 change, it is now no longer the same PC, and thus has been moved, wether or not activiation triggered.