You can also check your Recycle Bin to see if the deleted files are there. Check the Poser runtime to see if the files were accidentaly moved from the Daz folders to Poser.

To do a System Restore click on Start in the lower left corner.
Then Control Panel > Performance & Maintenance
and click on System Restore in the upper left of that menu.
Use the deafult "Restore My Computer to an Earlier Time" and click next.
You would then choose a date on the calendar before this happened and restore.
If you installed any software after the date you choose, you will need to re-install that.