1. Click the orange Firefox button, then select options to open the options window. If you have the menus displayed instead of the Firefox button, in the Tools menu select Options.
2. Go to the General panel
3. Change the setting "When Firefox starts" to "Show my windows and tabs from last time"

using Tools then Options then General panel set to show my windows and tabs from last time selected , window opens to say closing n tabs, are you sure you want to continue with options close tabs or cancel?

This wasn't happening before I updated to firefox 4, I could leave multiple tabs open and close the browser.

I have just tried on another laptop and it allows me to leave open several tabs when closing browser.

I'm not closing the session down as don't want to close the tabs!!! so can't say if they will restore on reopening. The other laptop is doing what I want but I don't what the difference is between them? As befoe update to 4 this laptop left tabs open for me?

If the sessions are not being restored, there may be a problem with the file that stores details of the session.

1. Open the profile folder, for details of how to find it see https://support.mozilla.com/kb/Profiles
2. Close Firefox
3. Delete sessionstore.js

Now restart Firefox a couple of times to see if it remembers the session.

I seem to have got it to do what I want now, must have a gremlin, don't know what I did, thanks for trying to help me.

Owner, the simple insurance is to always close FF with task manager by ending the process. When you boot FF back up you get an "Oops" window that says FF is having trouble restoring your tabs.

Don't worry, there are two tabs on the bottom, Restore Tabs, and Start New Session. Just click Restore Session, they all come back.

Always.