I have a baffling problem with a SATA HD

G'Day to all.

I have a baffling problem with a SATA HD. My computer is equipped with a 20gb IDE HD for my "C:" drive, and an 80gb SATA HD for my "D:"(Data only) HD. Running a bit short of space on "C:" I bought a new 250gb SATA HD, with the intention of installing it as "D" and promoting the 80gb SATA HD to "C:"

In the process of trying to transfer the contents of the old 20gb "C:" to the new 80gb I somehow managed to screw things up beyond belief. I used Paragon Partition Manager to partition and format; that went fine as usual, but the business of trying to clone the OS and software from the old 20gb HD to the 80gb HD resulted in the 80gb HD now being reported by Partition Manager as 346gb, unallocated space, and unresponsive to any attempt to make changes to it. Can you give me a clue as to what I might do to get started on correcting this issue? Many thanks.

Pinch