1.power off the phone

2.press and Hold Volume Down Power key for 3 to 5 seconds

3.release both the keys

4.now pop up menu appears

5.go to "RECOVERY" with volume down key (don't use vol up)

6.to select press volume up key

7.ofter few sec android exclamation logo comes

8.to see reset menu press one or two times both vol up and power key
at the same time (one click both)

9.go wipe/data with volume key's to select press power key

That's All...........