If you want a blank tab, enter about:config into the address bar, hit the return key on the keyboard, and change this setting:

browser.newtab.url - change to about:blank

Try to reset some preferences to the default with the SearchReset extension:

• https://addons.mozilla.org/firefox/addon/searchreset/

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 make any changes on the Safe mode start window.
• https://support.mozilla.org/kb/Safe+Mode

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

If you do not keep changes after a restart then see:

• http://kb.mozillazine.org/Preferences_not_saved
• https://support.mozilla.org/kb/Preferences+are+not+saved

Go to Add ons - Extensions and remove Proxy tool (by 22find).

Hi,

To remove 22find.com do the following:

1. Enter “about:config” in url bar in order to open settings page;
2. Write “Keyword.url” in the search box. Right click it & reset it.
3. Write “browser.search.defaultengine” in the search box. Right click it & reset it.
4. Write “browser.search.selectedengine” in the search box. Right click it & reset it.
5. Search for ‘browser.newtab.url’. Right-click and reset.

Very often more than one browser is affected by hijackers like 22find.com, if you need to remove it from other browsers, follow these 22find.com removal instructions.