i have a bios pass, a hdd pass, a grub pass, and of course my main login pass to windows, backtrack, or ubuntu. basically if you lock the bios, boot first from hdd (nonremovable), and dont let people remove the cmos battery :P you will be fairly secure. that is if you simply want to prevent access to the machine it self. you said that you are talking about a laptop, many laptops have a builtin hdd locking feature, look and see if yours does.