Start Firefox in Safe Mode to check if one of the extensions (Firefox/Tools > Add-ons > Extensions) or if hardware acceleration is causing the problem.

• Switch to the DEFAULT theme: Firefox/Tools > Add-ons > Appearance
• Do NOT click the Reset button on the Safe Mode start window

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

You can use the SearchReset extension to reset some preferences to the default values.

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

Note that the SearchReset extension only runs once and then uninstalls automatically, so it won't show on the "Firefox > Add-ons" page (about:addons).

You can check the browser.newtab.url pref on the about:config page and set that pref to the URL of your preferred new tab page.

• the default new tab page with the tiles is about:newtab
• the default home page is about:home
• for a blank page you can use about:blank

You can open the about:config page via the location/address bar. You can accept the warning and click "I'll be careful" to continue.

• http://kb.mozillazine.org/about:config

I appreciate your help but "I" could not get it to work. I had problems starting with "safe mode" and every step after that. Maybe I should just uninstall firefox and start over again. I am just wondering if I should do it before or after installing Windows 10.

Hi, just try running SearchReset which should reset your New Tab page and a few other things to default. If it doesn't, further investigation will be needed.

Did solve the problem. It removed my home page but that was it.