Firefox keeps dumping my bookmarks

Firefox, every week or so, loses all my bookmarks and toolbar bookmarks. They're just gone, no error messages or anything. This is very frustrating and annoying, since I often have information I need in my bookmarks, and I keep links to my commonly used URLs (email, banking, etc) in my toolbar. Has anyone else run into this?

Have u deleted ur history?

Uh... no. You'd think I'd notice if I'd deleted them myself. No, the problem is that all my bookmarks are there at night, and then when I open it the next morning they're gone. In fact, my history is still intact.

I just tried this:

"Click start/search/all files and folders and type bookmarks. Click search.

You should see a list of all your bookmarks, the firefox bookmarks will have a little firefox logo on them.

Locate the latest file with a date next to it. Right click on the file and select copy, paste the file to wherever you want. Close the search window.

Open Firefox and click on bookmarks/organize bookmarks. Click file/import and check the from file button and click next. Browse to where you pasted the bookmarks file and click open. You should now have your bookmarks back.

Regards Howard"

It didn't work. The only bookmarks files that the search found were a) the one currently in use by firefox, which is empty and b) old exports that I did to back up my bookmarks, ages ago.