In the Downloads window, to clear one downloaded file - right-click that file and select Remove from List. To remove them all - use the Clear List button at the bottom of that window.

Thanks, but when I pull up the download window it is empty. I'm not very tech savvy, and may have asked the wrong question. Here's my issue: when I type a single letter into the address bar, several addresses appear in a drop down box. E.g., I type y and several yahoo-related addresses appear. My question: how can I clear all those old addresses?

Do you want the files to be removed from the hard drive?

The Firefox download manager doesn't have that feature.
You can only clear the list if you have set Firefox to remember downloads, otherwise Firefox will remove entries automatically.

• Tools > Options > Privacy > History: "Remember what I've downloaded"

See also:

• Download Statusbar: https://addons.mozilla.org/en-US/firefox/addon/download-statusbar/