It looks like the 100mb System Reserved partition which boots Windows 7 was somehow deleted and is now unallocated space.
Regardless of reason, you must now recover System Active MBR to the Windows 7 HD for it to boot independently without the Vista HD.
To do this unplug the Vista HD, boot from the Windows 7 DVD Repair console or Repair CD, mark Windows 7 partition Active: Partition - Mark as Active
Next boot back into DVD Repair console or Repair CD, click through to Recovery Tools to run Startup Repair
up to 3 separate times with reboots until Windows 7 starts on its own.
You can also recover the 100 mb unallocated space into Windows 7 while marking Windows 7 active using free Partition Wizard bootable CD
before you run the repair.