So....2 drives
Disk 0 = 500GB which is the current C drive, and Disk 1 = 120GB, which is presumably the old 32bit C drive.
Correct?
And you installed the 64bit OS on the 500GB drive with both drives connected.
So the result is, your boot options show both OS's.
You need to remove the boot option for the old 32bit OS, and you need to Format the D partition, which contains the 32bit OS.
(if I am correct in my assumption above)