System Restore seems to back up and replace certain file types.
If your data has been somehow deleted, undoing the last restore might help. It might also also make things worse as almost anythihg you do on your pc involves writing to the HD, potentially overwrting any deleted files.
It may be worth trying a data recovery app. first, to see if you can locate and restore your missing files with that first.
It is better to d/l and run the recovery app. and recover files on a separate partition , if possible.
Here is a small recovery app. which runs just by right click and Run as Admin.
Hope it helps.