Can someone explain how this happened?

I have 2 hd's installed, 1 320gb with vista, 1 160gb with win7(64) and now I installed a new 1tb hd and wanted to do a fresh install of win7 using upgrade media. When I first installed win 7 on the other drive I had to install win xp or vista first and then do the upgrade. This time I booted from the dvd and installed win7 without any verification and I did not have to install all the mb drivers for sound or lan or anything else. All my past fresh installs forced me to install the drivers and then I could get online but this time it was not neccessary. I should probably mention before I decided to install the os I formatted the new drive because I was going to use it for data only but changed my mind. Am I missing something?

That is pretty strange that you got it to install without accually doing an upgrade. Windows 7 even in the betta stages never needed really any drivers on anything I installed it on though, most I did was update the ones that were there.