ok,so here's how it happened, i just bought my MBP on 27 dec, around like a month ago and you get this registration form at the beginning of the setup right? at that time, my MBP is still using 10.4.10 ( so basically it's tiger ) and i did the registration form ( its done and sent ) the next morning, i tried to install the Leopard which comes in the box, and after i did, the same setup was asked for us to fill it in right, ( the registration form stuffs ) but the internet was down at that time, so i thought i can cancel the registration form and do it when the internet backs up, because usually it can be located on our Home Folder, but then later, when the internet backs up, i wanted to do the form registration, but it's not there so some of the expert on MBP asked me to perform this command in the terminal "sudo rm -f /var/db/.AppleSetupDone" that command basically delete the history that we ever did the assistant register form and it took us back to the 1st setup, and it actually did, i was taken back to the welcome screen assistant right after i reboot, so it ends my curiosity at once only to realize later on, does performing such task can cause any harm to my MBP? or like downgrade performance? well, though there is no difference at performance task, ( still as fast as ever) just curious does it totally save to perform that sudo task? thanks and finally, does anyone know how to re-appear the warning that appear on the 1st time we're about to use the Sudo command? because now it's not appearing anymore, but i would love it to re-appear again, the warning, that is anyone here know how to? i know it can, but there is no way i can know how to except the experts here =) it will be greatly appreciated by me thanks alot!