How to defeat screen lock pattern.

If you mobile usb debugging is on than you connect your mobile to computer and root your mobile get super user access to your root folder.

Depending upon your mobile the unlock file are at different location normally name of the file is pattern unlock. Edit or delete that file will reset your passcode.
There are many software which claim to recover lost passcode but i dont have personally tried those software.

Recover Android Device in case of Forgot password/pattern ...

visihow.com/Recover...Forgot_password/pattern_unlock_an_Android_d...

Scroll using your "Volume up and down" button until you find the "Factory Data Reset" option. Tap the "Factory Data Reset" option. Tap "Reset phone". This will erase all of your data, but it will allow you to unlock your Android mobile device.

How To Reset Android Password or Pattern Without Losing ...

? 3:44
https://www.youtube.com/watch?v=-VXnNh7-4BA
Jan 22, 2015 - Uploaded by Intellect Digest
Forgot Password On Android Phone or Tablet- How To Reset ... or Pattern Without Losing Data When You ...

How to bypass Android's lock screen pattern, PIN or p

Call them from another phone - If that one is really yours :)"smile"

How to Unlock Micromax Phone Using Hard Reset Using stock recovery and wipe data. This method will result In a full factory reset of your phone . How to do this?

1. Switch off, Pull battery.
2. Insert battery and Press and Hold Power+Volume up+Volume down together (different phones might have a little different method of booting into recovery mode, but this is the most general one).
3. You will then boot into recovery mode , use volume keys to navigate up and down and power key to choose.
4. Choose Wipe DATA
5. Choose wipe cache.
6. Reboot device.

You are done and your lockscreen is gone and phone has been hard reset. Please not this leads to permanent removal of data.
Unlock Micromax Android Phone using Android Debug Bridge In this we will use ADB (Android Debug Bridge) to unlock the device without losing any data.

1. First we need to set up ADB on device , you generally need these link of adbzip in the bottom or you can Google on how to install ADB in windows.
2. Just make a folder adb in c/root and copy the files.
3. Install drivers of your phone (Use PDAnet if you have problem with finding drivers).
4. Turn on USB debugging on phone. Follow : Setting->Development->USB Debugging (Turn On)
5. Open Command prompt in computer , and type cd C:/Android (Android here is the folder where my adb files are , change according to yours)
6. Then you can try following sets of command

Adb files rar download 2shared

The user account is linked to a google account. If you can remember the username and password of that account, you will be able to reset your lock pattern. Otherwise, you will have to perform a factory reset. You will lose all your data. This is a protective measure by Android to prevent data theft.

I would factory reset it, unless it's always the same app that is causing the hang, then simply remove the offending app.

All you can do is just an factory rest at the service centre free of cost if you have the original bill....

Try your pattern 15 times and a dialog box will appear that will link you to sign into your Gmail account where you can create a new pattern password.
If you don't remember the password for your Gmail account, you will need to complete a factory data reset. Factory reset will permanently delete all your data and customized settings, and will remove any applications you've downloaded and installed. SD and SIM card data will not be deleted.
With the phone turned off, press and hold the Volume Down button, and Power button for 10 seconds.

Wait for the screen with the 3 Android images to appear, and then release the buttons.

Press Volume Down to select FACTORY RESET, and then press the Power button.

http://samsung-codes-tricks.blogspot.com/2009/02/general-samsung-secret-codes.html
*2767*CUST#
Reset Custom EEPR0M

just dial *2767*3855# for restart samsung e2121