Type about:newtab<enter> in the address box.

What does your new tab page look like now?

If it doesn't have a cog wheel in the page (not on the toolbar outside the page) it could be some other page. To check its address, you can use the Page Info dialog. Either:

• right-click a blank area of the page and choose View Page Info
• (menu bar) Tools menu > Page Info

On the General panel, you can triple-click the URL to the right of Address to select it, then either Ctrl+c to copy it, or right-click>Copy, and you can paste it into a reply.

FredMcD said

Type about:newtab<enter> in the address box.

It shows the tiled new tab I want. But it is not what it coming up when I click on the + to open a new tab.

With Firefox 41 (and higher), it's no longer possible to customize the page shown in a new tab via changing the preference browser.newtab.url in about:config. Because of the fact that hijackers abused the preference in the past, Mozilla decided to remove it (see bug 1118285). Fortunately, by removing it, Mozilla also introduced a new API to bring this functionality back to life as an add-on. This add-on allows the user to choose a certain page in a new tab.

New Tab Override (browser.newtab.url replacement) https://addons.mozilla.org/en-US/firefox/addon/new-tab-override/

This is also available using Classic Theme Restorer (Customize Australis) {web link} Restore squared tabs, appmenu, add-ons bar, small button view and more on Australis UI (Windows/MacOSX/Linux + Fx 29+).

But before trying to fix it with an add-on, could you let us know what the current address of the page that appears on your new tab is? It could be something substituted by one of your existing add-ons.