Where you using Firefox Sync on the old PC? <br/> https://support.mozilla.com/en-US/kb/What+is+Firefox+Sync If not, were you using something else to store your bookmarks "online"? Like maybe Xmarks or Delicious?? If you weren't using anything for saving /sharing bookmarks online or for "syncing" your bookmarks, they aren't "online". Do you have the hard drive from the old PC? If so, maybe that hard drive would work long enough for you to be able to access your files on the old drive if it is put in a USB enclosure and plugged into the new PC? <br /> http://support.mozilla.com/en-US/kb/Recovering+important+data+from+an+old+profile