Installed styles seem to have disappeared from Photoshop Elements 15, but...

Hey guys 🙂

I had a number of styles installed in Photoshop Elements 15. Now, they seem to have disappeared. At any rate, I can no longer seem them - only the styles that came with the software. However, when I try to re-install them, the system won't let me because, apparently, they are already installed. But as I said, I simply cannot see them. Is there anything I can do?

I'm on Windows 11.

Many thanks in advance!