Set What Pages Open when Firefox Starts – Session Restore

This is a great feature you can use in addition to the home page settings. To save time, you can have Firefox open the pages you were visiting the last time you used it so you can continue where you left off.

1. At the top of the Firefox window, click on the Firefox button (Tools menu in Windows XP) and then click Options.
2. Select the General panel.
3. In the Startup box, click the dropdown menu next to “When Firefox starts:” and select what Firefox should display when it starts up.
   • Show my home page – Displays the home page(s).
   • Show a blank page – Displays a blank page. This loads quickly since you don’t have to wait for lots of tabs to load.
   • Show my windows and tabs from last time – Opens the pages you were visiting the last time you used Firefox so you can continue where you left off.
4. Click OK to close the Options window. .

Try it out: If you really want to get fancy, you can set a group of web sites as your home page and set Firefox to open the pages you were visiting the last time you used it. That way, you can pick up your work where you left off and have one-click access to your favorite sites. [source]