Mozilla Firefox dumped all passwords and bookmarks

I found an easy way to fix all this while I was playing around. If you go to your profile folder "C:\Documents and Settings\User Name\Application Data\Mozilla\Firefox\Profiles\xxxxxxxx.default" (for xp and the like, where xxxxxxxx is seemingly random letters/numbers). you can open the bookmarkbackups folder and open the latest one. If it's blank, go to the next latest one, and so on till you find a list of your bookmarks. copy that file, and hit the back button. delete the file "bookmaks", and then paste the previously copied file. Then rename the file "bookmarks". open firefox and it should work at that point. sorry about the wordiness

 

I'm not quite certain but it sounds like you are deleting a folder that contains the file you intend to paste, before pasting the file. This is a dangerous proceeding. ALWAYS paste a copy of the required file BEFORE deleting the folder it is in. The most likely result of deleting the folder before pasting the file inside it is an error message:

and you will have no file, especially if you decided to be tidy and empty your recycle bin before pasting the file or if you happened to be working across a network, when files are dumped completely, not put in the recycle.

So this is the order you should follow:

Find the file you want.
Copy the file.
Paste it to the new location.
Delete the folder the file came from.