You don't need to purchase Recover My Files to see if it will work. You can run the program in trial mode, find your photos and preview them in the results screen. If you can see them, then yes they can be recovered. Purchase an activation key online to safe them. If you cant find them, then they cannot be recovered.
Download the program from
www.recovermyfiles.com. To find your lost photo folder, you need to try two types of search.
I would start with a "Complete File Search" of the new drive letter specifically for the photo files (eg. the jpeg file types). This search may not bring back their original file names (the will be called "Recovered_Jpeg_1" etc.) so click on each file found in the results screen to see the contents of the photo.
If you dont find the photos in this search, then try a "Complete Format Recover" of the new drive letter for the default selected file types. This search will bring back the files and folders with full file and folder names.
These two searches uses slightly different recovery techniques so may give different results.
It is impossible to tell if your photos are still there until you run the search. Any of the old data that is overwritten by the new installation of Windows has been lost for good. Having said this, your photos were probably further down the hard disk, so I think you have a good chance.