Kind of odd situation. Have you tried a general search on the entire hard drive for a texture file that you remember? Just to see if anything comes up? Kind of hard to believe that the entire textures folder was purged just like that. Even if you intentionally did it, it certainly would be too big for the recycle bin. Even if deleted you can still try deep recovery utilities like WinUndelete (http://www.winundelete.com). Even if the files are deleted, their signature still remains in the system footprint for a while.