Delete the "Password" set for "administrator":
Remove the hard disk of the computer or to connect them.set it to another computer as a "secondary bootable device."
Log in to your Windows.
Go to "Windows" then find "System32"and then go to "config".
Delete the file "sam.exe" and "sam.log."
Now turn off the computer and remove the drive only.
Set the hard disk of the other computer and then log in.
(Note: This trick only works if the hard drive in FAT format.)