Recover missing Application Data and more?

Hey /g/, I really need your help here. My sister was using my computer and was a little too triggerhappy with the downloading and SOMEHOW managed to fill up my C drive completely. I was not aware of this until the next time when I restarted the computer and logged in under my name, and saw a blank desktop with a standard blank blue wallpaper (when normally I keep many files/folders on the desktop). Under My Computer I can see that there was literally 0kb left. I tried opening My Documents, but it was empty. All my programs are acting as if their Application Data has been erased (Firefox missing all my bookmarks, other programs missing saved usernames and passwords...)

I've decided to move on from this mess, backup any files that I can recover and reinstall WinXP. I've managed to locate everything in My Documents and on my Desktop but I have no idea how to find the firefox bookmarks I had saved. Considering I haven't backed up the bookmark file for quite sometime, I am desperate to find a copy of it. I've tried Run: "%APPDATA%\Mozilla\Firefox\Profiles\" but there's only the default bookmark file (from when you first install firefox).

I'd also like to know how to get hold of the other files in Application Data - or are they gone forever? For example, I really want to export a copy of the files uTorrent has downloaded, but I don't know how to go about doing this.

Please, can /g/ help me?

i recently had to restore my firefox bookmarks as well try

appdata\roaming\mozilla\firefox\profiles\xxxxxxxx.default\bookmarkbackups\

(the 'xxxxxxxx' are replaced with a unique txt string)

and you'll find files with a name like this

bookmarks-2008-07-30.json

find one with the data as resent as possible

then open firefox go to

Bookmarks>Organize Bookmarks

then
Import and Backup>Restore>Choose File...

then direct it to the file you found earlier

PS I'm using Vista the dir path might be different for you

Nope, I did that already - when I said I tried Run: "%APPDATA%\Mozilla\Firefox\Profiles\....". There's nothing in my bookmarkbackups folder either. :(

>>1-3
firefox.exe -p

try  searching 'bookmarks.bak'
and if you find that change the bak to html then go to

Bookmarks>Organize Bookmarks
Import and Backup> From HTML...

then choose that file

Try booting from a live cd.