You can check your home page setting using the method in this articles:

• Startup, home page, tabs, and download settings

However, if your setting is correct and Firefox is ignoring it, you probably have an unwanted extension. You can check the Add-ons page. Either:

• Command+Shift+a
• "3-bar" menu button (or Tools menu) > Add-ons

In the left column, click Extensions. Then, if in doubt, disable.

Often a link will appear above at least one disabled extension to restart Firefox. You can complete your work on the tab and click one of the links as the last step.

Does that free Firefox to use your actual home page?

Also, if you could, check your download history for the source page of this download that messed up your settings. You can right-click the item in Download History (Command+j) and Copy Download Link. Then paste that into a reply.

The download that caused my problem was: http://download.cnet.com/Solitaire-XL/3000-18516_4-10367332.html

I did restore to default, which then opened th e Firefox home page when I clicked on the icon, BUT when I tried to log on to my bank account ti opened the bank's home page and then when I clicked on the button for personal log on I was confronted with the Yahoo home page. I didn't proceed any further because I feared some form of spy ware was waiting to read my password and "memorable information" if I tried to log on via Yahoo.

I'm assuming you didn't previously log on to your bank using your Yahoo! account... There are some login methods that have you log in through a different site account (OpenID and Persona, for example), but it's unlikely your bank would switch without advance notice and lots of it.

Do all your current extensions look legit?

I am not familiar with malware cleanup for Mac, but someone else may have some suggestions or maybe there's something for Mac in our support article: Troubleshoot Firefox issues caused by malware.