Were all of your Soundpools purchased through the in-app Store? If not, then you are responsible for safeguarding these.
They should all be under the Soundpools Folder. Look in the Program Settings, Folders for the location of the Soundpools as per what you selected when you installed the program. In Windows Explorer, look there to see what you have. Purchases from the Store will be there under "Shop."
If all were purchased through the Store, then go to Program Settings and Cleanup Store. Reopen and log back in.
Check the Downloads tab and download and install everything.
If you still don't have all Soundpools, in the parameters for Loops, select "Add Soundpools," navigate to the root folder for Soundpools, and OK. Everything should show up.
If your previous Soundpools are somewhere else, then you'll have to figure out where.