What will you do if you forget your windows password ? . The first thing which you will do is to start your PC in safe mode and then check whether your administrator password is empty or not if it is empty then you are lucky enough to access to the computer by enabling safe mode and then using command prompt to know more 
click here but what if you have administrator password already in place. you may be thinking that format your windows and intall a fresh windows Xp, vista or whatever.
Well here, I'm going to tell you how to recover your login password in a few minutes without instaling anything in your pc or without breaking your head. well if you are interested in knowing 
how to reset your password using safe mode option  then try this post 
reset using safe mode.
here we will use a software called oph crack. which is an open source (GPL licensed) program that cracks Windows passwords by using LM hashes through 
rainbow tables. But you may be thinking whether it is a legal one. Yes it is completely legal according to 
Wikipedia.  But you should not use this software for illegal purposes like  unauthorized access to other’s system. I have tried this method in Windows XP, 
Windows Vista, and Windows 7 ultimate and it works perfectly fine for an alphanumeric password length up to 14.
The method is a very simple one. You just need to 
download  the software which is 452MB for XP and 532MB for Vista or Windows 7.  Ophcrack comes in bootable Live CD 2.1.0 ISO and installation files.  Here we will be using the Live CD method where no installation is  required. Follow the steps below:
Step 1: Download the ISO File For Ophcrack Live CD 2.1.0 From the links below: (Choose according to your operating system)
Windows XP:
Size: 452 MB
http://downloads.sourceforge.net/ophcrack/ophcrack-xp-livecd-2.1.0.iso
Windows Vista or 7:
Size: 532 MB
http://downloads.sourceforge.net/ophcrack/ophcrack-vista-livecd-2.1.0.iso
 Step 2: After the download is completed successfully burn the ISO file to a CD using a burning software. ISO files can be directly burnt (Just open with 
burners  like Nero etc.). You should not use data mode or any other mode to  burn. The CD is a bootable one. But if you do not want to use a CD, you  can very well use a 
USB Flash Drive to run the program. Click here To see the USB Boot Technique.
Step 3: Insert the CD to your CD/DVD drive. Restart the System. You need to set the boot order to 
Boot from CD  as the first option if you have not set CD drive as the first option.  To do this you need to go to bios setup and change the order. For most  of the systems the keys like DELETE, F10, F2, F12 etc are used for going  to the Bios setup. But here I have used the Boot Menu Key which will  show the available boot options during start up. For my System(Dell Vostro) the  boot menu key is F12. For Compaq Systems it is usually F9. So if you  know the Boot menu key then no need to change the order. Just Select  CD/DVD ROM from the menu.
Step 4:  After booting from the Live CD, wait for it to load and select Ophcrack  VESA mode(Recommended). If you have a graphics card you can try  Graphics Mode.
Step 5:  If you have more than one partition containing the password hashes it  will ask you to select one. But most of the computers will have only one  hash partition, so you may not see this step. Select any partition and  try if it asks you as shown below.
Step 6: Wait for Ophcrack to run and find your password. After getting the password you need,you can simply click exit even if the 
progress is not 100%. No need to wait till end.
Here I had set the password as bcoders. It took around 1 min 20 sec to find this password.
Step 7: After the process it will ask you to press any key to exit Ophcrack. Then Type ‘y’ to shutdown the System. 
Now start 
your system. Enter the password you have found. And that’s it, see how simple it is!
NOTE: There is no official version for windows 7 but Vista version will do your job.
This is for information purposes only. We are not responsible for any damages or illegal acts resulting from this information.