i have to send my mac in service, but before i have to save my data. i will receive a external hdd and thought to use time machine with it and my mac. after that i will send my mac in service. if they dont fix it or dont return it and i will buy a new mac, also with 10.6, will time machine make the new mac the same as old one, with all my folders and files? or do i have not to use time machine and backup file by file?