Accidently deleted entire external hard drive!?

While trying to organize my external hard drive into individual folders such as Pictures, Videos, Doents, I , while in the root directory attempted to delete a random file that was in the root directory. But without realizing (stupid Vista) pressing select and choosing the one file it highlighted every folder above it. When I hit delete I received the error message that the file was too large for the recycle ben delete permanently? I hit ok and poof every file on my F: drive was gone. I immediately shut the drive down so as to not overwrite any files. Does anyone know of any freeware that can reliably recover this data? I am scared to just try something for fear that my pictures (10 years worth) will be permanently deleted.