http://support.mozilla.com/en-US/kb/Recovering+important+data+from+an+old+profile You can try transferring the entire contents of your Profile folder '''into''' the Profile on the other PC, but that might cause problems - although that is lessened greatly being that you're using WinXP SP3 and Firefox 3.6 on both PC's. Note, the name of the Profile folder on both PC's must remain the same as they currently are, otherwise Firefox won't "see" the Profile and will automatically create a new Profile. You need to transfer the '''contents''' of the Profile folder, not the folder itself ''(unless you re-name it exactly)''.