You have to copy the file located in C:\Users\[YOURUSERNAME]\AppData\LocalLow\Adobe\Director 11\BurninRubber4\Prefs called XBR4GOTYData.txt to the same location on your new computer! This is also the location where you can put your BR3 save file (called XBR3Data.txt). If you have the World DOmination achievement in BR3 - this will unlock the Tank in BR4 ;)