I was running Windows XP Pro x64 with SP2. Made a new partition, installed Windows 7 on new partition. On boot, I could pick Windows 7, or older Windows OS (XP Pro x64 SP2, basically Server 2003 SP2).
I'm using DriveImage 2002 to mirror/remove my orig Maxtor (40GB) onto a WD (120GB) HD with Win xp Pro OS. I think my image was created properly (both hidden and active partition) and it seems to boot ...