You can check the target line in the Firefox desktop shortcut (right-click: Properties) to make sure that nothing is appended after the path to the Firefox program.

See also:

• http://malwaretips.com/blogs/remove-omniboxes-virus/

It was that! But the shortcut isn't in my desktop, but in my Toolbar. Anyway, very thanks for your help and time, cor-el!

The home page is actually called omniboxes.com. However, it is not enough just to remove this from the home page of your browser. The computer is deeply infected, I assume you also have SupHPNot.exe as an active process. This needs to be dealt with. You may scan your PC with some genuine and free antivirus like Malwarebytes. I would also recommend you to reset your browser as explained in this guide - https://www.system-tips.net/delete-omniboxes-trojan/

Omniboxes.com is one of the nasty browser redirect viruses used by cyber hackers to make money. It can replace your default homepage aggressively so as to force you to use its own search engine when searching the internet. To remove it, you can

Moderator removed link that promoted a download of paid removal software. Please read the Forum rules and Guidelines and the message that was sent to you, thanks.

Hi, Omniboxes.com is calssifed as a browser hijacker that modifies users' browser setttings and keeps redirecting them to its homepage and other unwanted websites. To remove it, you can try following the manual removal guide in this post which provides very detailed removal steps. Good luck!