You can look at the browser.newtab.url pref on the about:config page and set this 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

Hopefully changing the preference described by cor-el worked and you're all set up. If that didn't work or didn't stick, here are some potential diagnoses and remedies:

If Firefox won't let you edit this setting: you may have something called SearchProtect on your system. This needs to be removed from the Windows Control Panel. If the status says "locked" we will need to help you investigate an "autoconfig" file.

If Firefox lets you save your change but ignores it: one of your extensions may be overriding it. You can review, disable, and/or remove extensions on the add-ons page. Either:

• Ctrl+Shift+a (Mac: Command+Shift+a)
• "3-bar" menu button (or Tools menu) > Add-ons

In the left column, click Extensions. Then cast a critical eye over the list on the right and disable (or remove) anything unknown.

If the change works during your session, but at the next startup is back to the unwanted page: you might have a user.js file in your personal Firefox settings folder (your Firefox profile folder). This article describes how to track down and remove the file: How to fix preferences that won't save.