The following applies to Windows. It may be different on the Mac.
For each version of PowerDirector there is a separate folder in your documents folder:
c:\Users\%username%\Documents\CyberLink\PowerDirector\ with the version number.
So, if you had version 19 and have moved to 20, you will find in the above mentioned folder the folders \19.0 and \20.0.
Within each of these folders, PD stores all your customized items, including titles, which can be found in the folder MyTitles. The first title that you save in a version will be stored in a folder called Title_000, the next in Title_001 etc.
The titles you have made and saved in version 19 will be in the folder \19.0\MyTitles\ and have the sequence numbers _000, _001 etc.
The first thing PD does when it is started, is looking for all items, like titles, Masks, Transitions, Pips etc. and through all versions it can find in the above-mentioned folder, but also in a number of other folders such as the Program Files folder.
The collection of all items takes currently about 1-1,5 minutes depending on the speeds of your system and disk, and the number of versions and items you may have. (there is hope that this will become faster in the next installment).
Should you change system, or reinstall the operating systems, and you want your old items, you have to copy the above Cyberlink folder from the old to the new system. You must either reinstate the version folders, but you can also combine them into one folder (e.g. the latest version), however in that case you have to renumber all items so to make sure that there are no duplicate numbers which causes items to be overwritten. I think that because there may be items that have version dependent features, it is best to leave the version structure as is, so that PD can keep track if need be.

Hi, Thanks for that, but as you can see I've done that already and still no joy?

I had the same problem after reinstallation of my Windows system. For PD 20 apparently the proper order is: move all the title stuff in the folders mentioned and then install PD 20. I had to go as far as to uninstall PD and then install it again, but after that I got all the custom stuff back.
I think that with the changed approach where items can be downloaded directly from PD rooms, has also impacted the making inventory of the items from earlier versions, and impacted the time of getting all items loaded as mentioned.
Please let us know where the above works for you as it did for me?
And... maybe it helps if you also put in a suggestion or problem report to CL.