All of the bookmarks, passwords, etc. that I want to keep are on my '''laptop'''. If I've set up my Firefox Sync account on my ''desktop'', and I add my '''laptop '''to that account, will the "syncable" data from my ''desktop ''overwrite all the "syncable" data on my '''laptop'''? I've lost all my contacts on my phone before because of some overzealous syncing program and I'd like to not lose my precious treasure trove of bookmarks and passwords (that I may or may not remember anymore...) Tanks in advance.