By 'data' I mean your Bookmarks, Passwords, Form's Data, Certificate information, pages visited history, and some user preferences.
You can't copy/paste the entire profile folder, it won't work. Even if it did work, some of those files may contain the problems that brought about the need to create a new Profile in the first place.
But you can Right-Click, copy / replace these files, one at a time.
In W2K and WinXP, the \Document and Settings\ directory is hidden twice by default.
To access the \Documents and Settings\Application Data\ directory, you may need to set Windows Explorer to show System and Hidden directories and files.
In Windows Explorer click: Tools - Folder Options - View tab.
Check "Display the contents of system folders."
Under Hidden Files and Folders select
the radio button for "Show hidden files and folders."
Probably not required but I recommend that you:
uncheck "Hide protected operating system files."
uncheck "Hide extensions for known file types."
Firefox must be closed when performing the following: