Hard drive crashes are such a pain. Been there done that too many times to count and each time it takes two days to get things working the way they used to.

One thing you can check.

Look in the library display options and check to display the Extended Details panel.

Click on one of the files in the library that DO show up. The extended details panel should show the path of that file.

I can't remember if Poser 11 has the "Show in Explorer" link but if it doesn't you should at least be able to determine where the "good" items are located. And then you'd at least be able to determine if the items that DON'T show up are in a different runtime folder than the one Poser recognizes.