Please post back a screenshot of your maximized Disk Managment drive map and listings, using Snipping Tool in Start Menu. Attach using paper clip icon in reply box.
Normally you would mark the new Windows 7 partition Active, unplug the old HD with the System partition, boot into DVD or Repair CD to run Startup Repair - Run 3 Separate Times
until the new Windows 7 partition becomes marked System Active and boots on its own.
You can then plug back in the other HD, set preferred one to boot first in BIOS setup, boot the other one using the one-time BIOS Boot Menu key given on first screen. If you don't like this arrangement, install EasyBCD to the first booting HD, add the other OS on Add OS Entry tab to a Dual Boot menu.
But there are sometimes complications like a Logical partition which cannot be marked Active until converted. So its best we see the screenshot if you have any problems.