It sounds like you've copied the EXE to your desktop.
Uninstall the preview version.
Running the un-installer only removes the program from the Program Files folder. Your data stays.
There are three folders you need to know:
1. location of the EXE (should by under Program Files).
2. location of the Configure.xml file? (should be under %APPDATA%).
3. location of the logs and trunking data? (should be also under %APPDATA%).
#1 and #2 are normally controlled by a Windows short-cut.
#3 is a setting inside Configure.xml. The default is the same as #2.
Please install the current release version.
It will install the program under program files and create a start menu short-cut the sets the working directory to a folder under %APPDATA%.
That's the standard installation. Sticking to the standard installation will make upgrades much easier.
If you've manually copied files, created your own short-cuts, or are in the habit of launching the program from Windows Explorer - you're on your own.