I think the easiest method is to copy all of the contents of the old profile folder into the new randomjumblename.default folder.

Make sure you are altering your personal profile folder. This article can help you verify the location: Profiles | How to | Firefox Help.

I tired what I thought was that.... should I delete the almost empty new profile that FF4 created in my new PC.. then just import and rename the old profile as .default

If you delete the existing profile folder and copy over your profile folder, you can edit the profiles.ini file to match the folder name. That file should be here on Windows 7:

C:\Users\yourusername\AppData\Roaming\Mozilla\Firefox

in the old profile that I copied over there is a 'default.ini' file listed... what should I change that to... sorry if I'm being a pain.. just trying everything ..don't want to screw it up... thought this would be e-z...

Right so profiles.ini is at this level:

C:\Users\yourusername\AppData\Roaming\Mozilla\Firefox

And default.ini is in your actual profile folder at this level:

C:\Users\yourusername\AppData\Roaming\Mozilla\Firefox\Profiles\xzy.default

I don't suggest any edits to the files inside your profile folder. Those should remains as they were on your other PC.