Frank_Rizzo - 8:59 am on Jun 17, 2010 (gmt 0)
If XP try:
\Documents and Settings\YOUR PROFILE NAME\Application Data\Mozilla\Firefox\Profiles
Under there should be a random string of chars with your profile info.
there could also be a folder here:
\Documents and Settings\YOUR PROFILE NAME\Local Settings\Application Data\Mozilla\Firefox\Profiles
Search for prefs.js this should be in the main Application Data dir, whilst the Local Settings should just have cache info.
Copy your bookmarks file, uninstall FF, delete the directories, run something like CCleaner to delete orphaned registry entries.
Install FF 3.6, import bookmarks.