To enter Recovery Mode in Videocon v7400.
Switch off your Phone By reinserting the battery.
Press these keys together ( Calling key + volume up key + power key ).
When u see the android logo release all the keys and wait for 2 or 3 seconds.
You will be in Recovery Mode.
And there you can easily wipe userdata and remove pattern lock..
For video Reference you can do Same like Huawei u8150 hardreset procedure.