Install EasyBCD 2.0 beta
after doing quick registration to use beta, add the missing OS in Add/Remove by name, type and correct drive letter.
If the missing OS shows up in EasyBCD but won't boot, remove it and Add again.
If this fails to set up your dual boot correctly, please post back a Screenshot of your full Disk Management drive map and listings, as well as EasyBCD listings. Use Snipping Tool in Start Menu, attach file using Paper Clip in Reply Box.