1- Charge Micromax D304 upto 70 percent.
2- Switch off device.
3- Press & Hold Power and Volume UP key.
4- Press Volume UP to enter Recover mode.
5- Android Logo with exclamation mark appears, Press Power key.
6- Choose Wipe Data/Factory Reset using Volume down key and press Volume up key to confirm.
7- Select Yes-delete all user data using Volume up key.
8- Press Volume UP key to reboot system now.