I am still confused between launch and start date, but as suggested by nimesh and after trying out everything, I will go with this.
G4EF was launched on 12th July 2004, but the first post was made by shabbir, on 07-15-2004, 10:43 AM (here considering time as 10:43:00 AM).
So, from this calulation is as below.
Considering forum's first post on 07-15-2004 at GMT 5.5+ 10:43:00 AM.
So, Starting Date 07-15-2004, Starting Time is GMT 5.5+ 10:43:00 AM.
If you count for 07-13-2009, Time is GMT 5.5+ 07:15:00 AM.
The Result 1823 days, 20 hours, 32 minutes and 0 seconds can be converted into Seconds,
So equals, 157,581,120 seconds at 07-13-2009, Time is GMT 5.5+ 07:15:00 AM.