See this article https://support.mozilla.com/en-US/kb/Recovering%20important%20data%20from%20an%20old%20profile?s=Copy+Bookmarks&as=s .

Or if you can go and browse your old hard drive. Go to Program Files/Mozilla Firefox/ and double click on Firefox.exe . This will launch Firefox from you old drive you can then follow these instructions to export and import your bookmarks https://support.mozilla.com/en-US/kb/Backing%20up%20and%20restoring%20bookmarks .

thanks for the suggestions weather15 - the firefox help site you directed me to explains what ought to happen but i cant make it work. I shut my firefox browser on my new machine and attach the hard drive from my old machine. I can explore the contents of that drive but when i search it for the suggested folder " %APPDATA%\Mozilla\Firefox\Profiles\" nothing is found. when i try and open firefox from the old drive, the browser opens that is the new version that i have on my new computer with no saved bookmarks! Am I doing everything right?

Please follow the instructions on this webpage http://windows.microsoft.com/en-US/windows7/Show-hidden-files to show hidden files. Then click on Start --> Computer --> Your Old Drive -->Users -->Your Username --> APPDATA\Mozilla\Firefox\Profiles\ and follow the remaining instructions in the support article. Let me know if this helps.

thanks weather15. I had to explore and try a few things but in the end it seemed to work out. I think the guides you linked me to earlier were not the clearest that I've come across but they did the job. I'm not a technophobe by any means, but given that I only change computers every few years, I cant remember what i did last time, and anyway the processes are probably out of date. Now off to an 'outlook' forum to find out whether i can find some old saved emails on my old hard disc :o)