Hi

I recommend you have a read of this question that has more information and guidance.

Type about:preferences#general<enter> in the address bar.

There are two settings;

• When Firefox Starts

When the browser is started, what do you want to display. Many of us choose Show My Home Page.

• Home Page

When a new page is opened, what do you want displayed.

1. Use Current Page. Use what ever page(s) are open at that time.
2. Use Bookmark
3. Restore To Default. about:home shows a Mozilla home page with tools.

You can use any of these that you wish;

about:home (Firefox default home page), about:newtab (shows the sites most visited), about:blank (a blank page),

or you can enter any web page or about: page you want.

When I open firefox I get an unknown site called: my.com which I have no idea what it is. I want my home page to be Mozilla Firefox.... How do I get rid of this my.com??

Have you played/install any game from there site or there partner sites ? Most of the time when you are installing a game or a software it may be possible that home page is hijacked by there own search box. If you tried what "FredMcD" said and nothing changed then perform a full scan of your system from any of these malware scanner :

• Adw Cleaner
• Malwarebytes
• Hitman

As a guess it may be possible that you have played these games on Android/iPhone devices with your login credential and due to sync it comes to your pc.