Password
 protecting a laptop does not ensure  data protection, the password 
protection of laptops provides a false sense of  security. Passwords on 
laptops are good to implement to prevent unauthorized  access, however 
when a thief steals a laptop and has time, getting around the  password 
is quite simple. There are also issues if there was no way to get  
around passwords, as even admins forget them and need access to the 
system.  Passwords are good to have, but will not stop a thief from 
accessing the device,  only slow them down a bit. Here is a quick run 
through of some common techniques  for getting around the passwords for 
different platforms:
 
Windows XP & Vista
 
Windows can be cracked using several available  tools one popular one is
  OphCrack,
 which is free. The software can works with Windows, Mac OS X and  
Linux. It comes with a LiveCD version which automates the retrieval, 
decryption,  and cracking of passwords from a Windows system. The latest
 version uses a new  faster technique using rainbow tables and can crack
 99.99% of alphanumeric  passwords of up to 14 characters in usually a 
few seconds, and at most a few  minutes. The software works with older 
versions of Windows as well.
 
 
Another commerical product is 
Proactive Password Auditor from
  Elcomsoft. The software utilizes similar techniques to OphCrack but 
with a bit  more automation and a friendlier user interface. The product
 basically makes  password a mainstream technique that anyone can use to
 gain access to a  system.
 
 
OS X
 
For
 OS X 10.4 The root password can be easily  reset in OS X by booting the
 system from the Mac OS X installation CD and  selecing the Reset 
password option under “Utilities” from the installer screen  and follow 
the directions.
 
OS X 10.5 can be reset using single user mode.  (hold down ‘Command’ and ‘S’ during reboot or startup.)
 
At the prompt, type fsck -fy
 
Type mount -uw /
 
Type launchctl load  /System/Library/LaunchDaemons/com.apple.DirectoryServices.plist
 
Type dscl . -passwd /Users/username  newpassword replace with the real “username” and follow with the new password,  as shown.
 
Linux
 
Boot Linux into single-user mode
 
- Reboot the machine. 
 
- Press the ESC key while GRUB is loading to enter the menu. 
 
- If there is a ‘recovery mode’ option, select it and press ‘b’ to boot into  single user mode. 
 
- Otherwise, the default boot configuration should be selected. Press ‘e’ to  edit it. 
 
- Highlight the line that begins with ‘kernel’. Press ‘e’ again to edit this  line. 
 
- At the end of the line, add an additional parameter: ’single’. Hit return to  make the change and press ‘b’ to boot. 
 
- Change the admin password
The
 system should load into  single user mode and you’ll be left at the 
command line automatically logged in  as root. Type ‘passwd’ to change 
the root password or ‘passwd someuser’ to  change the password for your 
“someuser” admin account.  
- Reboot
Enter ‘reboot’ to restart into your machine’s  normal configuration. 
 
These
 are just a few techniques used to get  around password protection on 
laptops. The first thing that should be  implemented is making passwords
 longer, a 14 character password can be cracked  in a matter of minutes.
 Most IT administrators require a password of 8  characters, this is not
 sufficient. It is better to devise a phrase instead of  just a word.
 
Encryption, Encryption, Encryption
 
If
 you have sensitive information on your  system, it is important to 
ensure that the data is encrypted, many operating  systems have this 
built-in and there is also free encryption tools such as 
TrueCrypt
 that provide  excellent encryption, so even if your password protected 
laptop is cracked, your  data is still secure, just make sure you use a 
different password for your  encrypted drive.