Open an Explorer window, then choose Organize>Folder and Search Options. Click the View tab and under Hidden Files and Folders, select to show hidden files and folders.
FWIW, I don't have Firefox preferences I care enough about to transfer the profile over. I normally just backup my bookmarks and passwords and re-import them. You could also set up Firefox Sync. It'll sync your Firefox preferences between all your PC's.
Mozbackup also works well. Used for years.
http://download.cnet.com/MozBackup/3000-2242_4-10260383.html
Open an Explorer window, then choose Organize>Folder and Search Options. Click the View tab and under Hidden Files and Folders, select to show hidden files and folders..