These are very rare situations but sometimes system crashs, etc... happens. While installing application you agreed to take proper backups of your own files. By not taking periodical backups of your precious files you are taking full responsibility according to EULA.
Your can try to restore your exact file structure in a new and unused disk partition. You need a quality file recovery software to do so. We can't recommend a special product you have search in google for the right program for this job. You should ask further questions to this software's support team.
