Default (help) lg double play c729 flashing

i have lg double play and suddenly it started to hang and showing force close all app...so i want to flash it and i downloaded this file from this thread so somebody please guide me how to use this file to flash it or please post a tutorial..

http://forum.xda-developers.com/show....php?t=1765996

somebody please help...
thanks...

i cant even hard reset ..when i try to hart reset it with settings or key combination it just shows format screen but when i restart my fone its the same as before...so this is the reason to flash my fone...