See "Why weren't my tabs and windows restored?" on Common questions after upgrading from Firefox 3.6, hope it helps.

about:home - doesn't come up with anything. Still no previous restore session. I think it may have been more of a 'hanging' issue, and then I forced quit firefox, after waiting for so long, as it wasn't responding. There are 3 'sessionstore-1.js, -2, and -3' files. The 3rd one was from the previous day, the first 2 are from months ago. The 'sessionstore.js' file is the current one today. Does anybody reckon I need to go into creating a new profile to get all my previous tabs? Also, if I copy and keep the 'sessionstore-3.js' then will that get my tabs back?

Does anybody know how i can get my tabs back please?

There shouldn't be any numbered sessionstore-##.js in the Firefox Profile Folder

• http://kb.mozillazine.org/Profile_folder_-_Firefox

The presence of such files usually indicates that that was a problem with accessing the main sessionstore.js file that prevented Firefox from renaming the temp file with the number.
In this case you may be lucky that the file with the highest number may have that session.
You can try to rename the file sessionstore-3.js to sessionstore.js to see if that brings back the lost tabs.

If you use the Time Machine then you can try to restore a copy of sessionstore.js from around the time that you lost that session.