I downloaded and ran Testdisc on my Windows 7 32bit system. Here are the steps I ran - it tells me "number of bytes per sector mismatches" and "No partition found or selected for recovery".
1) I highlighted my drive with the deleted partitions and clicked "Proceed"

2) EFI GPT was already highlighted by default so I hit enter.

3) - I then selected "Analyse"

4) - This is the next screen - "Quick Search" was selected by default so I hit enter

5) - This screen appeared briefly:

6) Then this screen appeared - "Continue" was highlighted by default so I hit enter

7) I selected the second item, "NEW VOLUME", which is what my old partition was named, then hit enter

8) Then it says "No Partiton found or selected for recovery"

Any idea what's happening here? It seems like it expects to find a 6TB disk instead of a 3Tb one if I'm reading it right, according to screenshot 6. I can see the list of all my files on the drive if I select the partition and hit "P" to list all files. But for some reason it doesn't seem to want to let me recover the entire partition. What can I do?