Hi dinoshim,

check if this is helpful : see in the next link the solution chosen from Stecyk and cdhollis reply

https://support.mozilla.org/el/questions/927606?s=DELETE+YAHOO+TOOLBAR&r=2&as=s

thank you

The Reset Firefox feature can remove many unwanted extensions with only one click.

To Reset Firefox do the following:

1. Go to Firefox > Help > Troubleshooting Information.
2. Click the "Reset Firefox" button.
3. Firefox will close and reset. After Firefox is done, it will show a window with the information that is imported. Click Finish.
4. Firefox will open with all factory defaults applied.

Further information can be found in the Refresh Firefox - reset add-ons and settings article.

Did this fix your problems? Please report back to us!

You may not recognize the name of the extension that adds the toolbar.

Start Firefox in Safe Mode to check if one of the extensions or if hardware acceleration is causing the problem (switch to the DEFAULT theme: Firefox/Tools > Add-ons > Appearance/Themes).

• Don't click the Reset button on the Safe mode start window or otherwise make changes.
• https://support.mozilla.org/kb/Safe+Mode

• https://support.mozilla.org/kb/Troubleshooting+extensions+and+themes

Did you check in the Control Panel > Programs if there are programs that were added recently?

Try to boot the computer in Windows Safe mode with network support (press F8 on the boot screen) as a test to see if that works.