Sync isn't a backup system it sync between sync server and devices and if your computer was the main system that had the data before reinstalling then chances the data was wiped clean when you connected to the sync and it sync the new data that didn't anything and replaced what was still present from other devices is now gone. What should've done first was backup your profile, data, bookmark, login data to usb or html file to restore back for the new setup but if this wasn't done then there is no data to be found now.