During Installation of Vista, I choose the option of fresh installation. I had no drive space left on the HDD and after doing window update proceeding to installation. I was prompted to select, out of all drives on PC to choose "Where do you want to install Windows?" option. At this point I already knew that I was out of drive space, but I was not prompted to format any drive. At this point I had to start all over.
Windows did alert me before installing updates, but I figured being Microsoft they would offer this option at this point, they have in the past, but without the get updates option.