Logger Pro 3.6.1 and earlier, when installed on Windows, used a default path for experiment files of:
C:\Program Files\Vernier Software\Logger Pro 3\Experiments
Logger Pro 3.7-3.8.0, use a default path of:
C:\Program Files\Vernier Software\Logger Pro 3\en-US\Experiments
Logger Pro 3.8.2 and later versions use a default path of:
C:\Documents and Settings\All Users\Application Data\Vernier\Logger Pro 3\en-US\Experiments
Vista and Windows 7:
C:\ProgramData\Vernier\Logger Pro 3\en-US\Experiments
As a result, it may appear that custom experiment files have been deleted when newer version are installed. They have not been deleted, nor have they been moved. They are merely in the same place they were originally. LP is just looking in a different location by default.
By default Logger Pro initially looks in its Experiments folder. Older custom files created with earlier versions won't be in the new location, but they will remain in the old location.