Every single month since Spring of 2007, one or two major updates and upgrades are downloaded + installed with your consensus to do so, everytime it happens. And, on these dates you will have to do a system restart.
So, just before you can sign-in with your profile's configuration and password, you will see the message that windows is upgrading its own configuration and, showing you the percentage of progress from doing just that. Then, the welcome screen shows up and then, your avatar and the request for you to enter your password.
Therefore, a new machine needs to skip a lot of these gradual updates/upgrades by installing the Service Packs first, in the case of a fresh install of Vista(6.0). For Win.7 and, for the newest buyers of PCs with their preloaded O.S., right now, have only the last 6 months of major updates/upgrades to put it to current stable use of it all. As of this mid-Spring of this year, the newest buyers of PCs will have, only, to download the Service Pack 1 for Win. 7(6.1.7600)+ install it, one reboot and only one reconfiguration of their machine. Who knows, maybe, it will bring this renewed O.S. to version 6.2.????. It is, somewhat planned, for Win. 8 to be version 6.3.xxxx or, up to version 6.5.xxxx at official retail release(possible burnt onto the newest PCs' HDD upon availability to any stores near you).
Happy upgrading, updating and, reconfiguring. For the next 2 months, at least.