"catalog files for the content indexer" wiped my harddrive!

Hi people, new poster, please please please say you can help!

I was copying things from my Mp4 player onto my external harddrive, when the notice that i had not enough disk space came up.
It launched "disk cleanup" and since there was nothing else in the rubbishbin it offered to "catalog files for the content indexer".
I clicked on it, and it began this long hefty operation. I cancelled it because I noticed that all my files had disappeared. That is, EVERYTHING on the external harddrive is now gone, aside from the folders where they used to live. So i have a harddrive full of folders with nothing in them except the old thumbnails.

Photos, Music, Video and Documents, all disappeared. its a FAT32 if that helps anyone, and the harddrive when i look at its properties now says still that out of 30 gigs there are only 5 free, so the files must be there somewhere.

I've tried system restore, viewing hidden files/folders, system files, all of it. Nothing seems to work.
PLEAASE help.
Ive also tried file restoration software, but it restores other files, nothing of the stuff that's gone missing.
HELP!