Type about:preferences#home into the Search/URL bar. At the top of the screen that comes up click the box that says "Firefox Home (Default)" and the choose "Custom URLs." Another box will appear below into which you can paste or type the URL of the web-site you wish to use as your Home Page, ie something like ebay.com.

Thanks for the feedback. The proposed solution didn't solve my problem in part, I suspect, because my software/system setup didn't seem to match the proposal. I was able to make some progress and I'm fully functional after a few keystrokes after startup.