Windows 7 is on a logical drive so that has to be converted first using Partition Wizard CD.
The first partition shows empty. May have been factory OEM partition but Dell utiltiies lose their links to Windows 7 clean install and won't be needed in Vista so you can wipe that partition also.
Boot Partition Wizard bootable CD, select 1 for screen res, rightclick each of the first 3 partitions to Delete, click OK after each.
Next rightclick Windows 7>Modify>Convert to Primary, OK, Apply all steps.
Allow to complete steps so far, then rightclick Windows 7>Modify>Set to Active, OK.
Again rightclick Windows 7>Resize, drag left grey border all the way to left side of disk, then if you want to leave room for new partitions drag right grey border to left to resize Windows 7 partition as desired, OK, Apply all steps.
Now boot the Windows 7 DVD Repair console or Repair CD, accept any offered repair, restart, continue to boot back into Repair>Recovery Tools list to Run Startup Repair up to 3 separate times with reboots. Startup Repair - Run 3 Separate Times