See How to set the home page

Incidentally, your Flash player is out of date and consequently a security risk. See http://www.adobe.com/support/security/bulletins/apsb11-12.html

Update via http://get.adobe.com/flashplayer/

Unfortunately, I already tried that procedure. By the way, it says use the tools button if you're running XP. The thing is obviously out of date, because you also have to use the tools button if you're stuck using Windows 7.

Anyway, after using that "reset to default" what I get at opening is a completely blank page, with its tab labeled "New Tab". I DO NOT get the supposed Firefox default homepage, with the Google search bar and, supposedly, a restore last session function.

Firefox 4 saves the previous session automatically, so there is no longer need for the dialog asking if you want to save the current session.
Use "File > Exit" or "Firefox > Exit" if you want to restore multiple windows.
You can use "Firefox > History > Restore Previous Session" to get the previous session at any time.
There is also a "Restore Previous Session" button on the default about:home Home page.

Another possibility is to use:

• Firefox (Tools) > Options > General > Startup: "When Firefox Starts": "Show my windows and tabs from last time"

I see the word "Norton" in your screenshot. That security product is currently incompatible with Firefox 4.0.1, see: Norton product compatibility with Firefox Updates

Perhaps that's where the problem lies. Try disabling it and see if it makes any difference.

Actually, it is compatible. They'd released a patch so Norton'd work with 4.0, now they've finally fixed it for 4.0.1. I had to go back to 4.0 for a bit while I was waiting for them to do it. They were a little behind the power curve on the latest fix.

If someone's running Firefox 4.0.1 and Norton, they need to open their norton internet security and manually run the live update. The live update that runs automatically all the time doesn't pick up the fix.

By the way, systems running XP and Win7 don't have a Firefox button. The stuff is in the Tools.

And after when I did "reset to default" for the homepage I did NOT get anything but a blank page when I open Firefox. Look at the screen shot I posted. I DO NOT get the Restore Previous Session button everyone claims exists.

Restore previous session is a menu item accessible by clicking the Firefox button. See screenshot.

Thanks for the tip about the Norton patch.

P.S. If you don't see the button, it's because you have "Menu Bar" enabled. Right click a blank part of the Tab Bar, and then click "Menu Bar" at the top to uncheck it.

Statement posted by tmaca:

   "Actually, it is compatible. They'd released a patch so Norton'd work with 4.0, now they've finally fixed it for 4.0.1. I had to go back to 4.0 for a bit while I was waiting for them to do it. They were a little behind the power curve on the latest fix.

If someone's running Firefox 4.0.1 and Norton, they need to open their norton internet security and manually run the live update. The live update that runs automatically all the time doesn't pick up the fix."

My Response:

 I did as you suggested but I still do NOT see a Norton toolbar in the toolbar area. I relaunched Mozilla just to make sure.  See included image of MY toolbar area. I use Windows Vista with the latest updates and Norton ISS vs. 4.3.0.5
 Thanks for a reply and have a good day.

@ luigey, see If your program has updated to version 18.6.0.29 the toolbar is compatible for Firefox 4.0.1

Thanks, already did it. But I had to revert to Firefox 4.0 for almost 2 weeks while I waited for Norton to fix their NIS.

For if you go back to Firefox 4:

Firefox 4 saves the previous session automatically, so there is no longer need for the dialog asking if you want to save the current session.
Use "File > Exit" or "Firefox > Exit" if you want to restore multiple windows.
You can use "History > Restore Previous Session" to get the previous session at any time.
You may need to click the orange/gray Firefox button to see History.
There is also a "Restore Previous Session" button on the default about:home Home page.

You can set the warn prefs on the about:config page to true via the right-click context menu or toggle the value with a double left-click.

• browser.showQuitWarning, see http://blog.zpao.com/post/3174360617/about-that-quit-dialog (Fx 4)
• browser.tabs.warnOnClose, see http://kb.mozillazine.org/About%3Aconfig_entries
• browser.warnOnQuit , see http://kb.mozillazine.org/browser.warnOnQuit
• browser.warnOnRestart , see http://kb.mozillazine.org/browser.warnOnRestart

To open the about:config page, type about:config in the location (address) bar and press the "Enter" key, just like you type the url of a website to open a website.
If you see a warning then you can confirm that you want to access that page.
You can use the Filter bar at to top of the about:config page to locate a pref more easily.

I never really ditched Firefox 4, I just had problems using 4.0.1, mainly 'cause Norton NIS wouldn't work right with it. I had to go back to 4.0 until Norton fixed their software, which took about 2 weeks.

And while I knew how to get my pages back a couple of ways, including out of history, it was still a lot easier to have an automatic option to restore the previous tabs as soon as the browser opened. Firefox was obviously saving the info, you just had to click the restore "Yes" to get it all back, or the "No" to start over again. One single click, either way. I just do not see any advantage whatsoever in having gotten rid of that.

Another possibility is to use:

• Firefox/Tools > Options > General > Startup: "When Firefox Starts": "Show my windows and tabs from last time"