@Dark Star Am on gnome 2.22.1
@QwertyManiac Am pretty much a noob as far as linux is concerned

. I tried the location u had mentioned ( /etc/X11/gdm/custom.conf ). There exists a custom.conf inside the gdm directory, but its contents are different. The custom.conf contents are given below.
Code:
# GDM configuration storage
[xdmcp]
[chooser]
[debug]
Well it worked. I edit the conf file so that it includes the following
Code:
[daemon]
TimedLoginEnable=true
TimedLogin=yourusername
TimedLoginDelay=0
Now am able to login automatically. Thanks guys !!