MAMEWorld Forums - The Loony Bin - Boot question for current system gurus

When I first got my computer, Vista was installed on the primary drive (250GB). I later purchased 7 and put it on my second drive (500GB), and eventually deleted all the Vista OS files on the original drive, but didn't format it. Good thing, as I now realize the computer still boots off of that drive. I just purchased a 1TB drive to replace the 250GB drive and figured there would be no issue since the OS is on the 500GB drive. "Non-System disk..." error. Ah, forgot to swap the drives to make the 500GB drive the first drive. Of course that didn't work. My information is probably dated (IDE days, current drives are SATA) or I am forgetting something important. SO, I looked up the issue and was pointed to this technet article:

http://technet.microsoft.com/en-us/library/ee829686

Only the first part applies as I don't have any other OSes installed. My question is, why do I need to make a tiny partition on the 500GB drive to make it a system partition? My last experience with trying to shrink a partition to make room for another one was complete failure with having to reformat. I assume also it will be a bad idea to try to shrink my Win 7 partition while running Win 7 leaving me with shrinking the larger 350GB partition on the same drive, unless I do it from a bootable CD like Ultimate Boot CD. Will it work to have a system partition in the middle or end of the drive?

In any event, the instructions involve just copying over a few simple files to the new tiny system partition. In light of that, why do I even need the new partition at all? Can I just copy these files to my Win 7 partition and leave it there? If not, why not? Thanks. It sounds the user below says he did this, but I want to be careful that I don't mess this up, which is why I am asking here before I go ahead and try myself: