I can't locate downloaded files, if indeed, they were saved to the downloaded files location
When I download a file everything is okay except I can't locate where the file ended up. It doesn't go to the designated folder on my computer.
ప్రత్యుత్తరాలన్నీ (1)
If you remember download (Tools > Options > Privacy > History: [X] "Remember download history") then you can right click a file in the Download Manager (Tools > Downloads) and click "Open Containing folder".
If that item is grayed then the file isn't (anymore) in that location and in that case it may have been removed by anti-virus or cleanup software and you need to check in those programs if there is a log about that and adjust the settings.
See also http://kb.mozillazine.org/Unable_to_save_or_download_files