My laptop is very hot from bottom and its very difficult to rest it on lap. The laptop has dual VGA cards (intel and radeon). I have disabled ATI card by blacklisting 'radeon' module. Although it increases battery life but it is still very hot.

How can make it a cooler?

Do not set it in your lap.

Air must be able to circulate around the case.

There may be some way to bring that temperature down!

how old is it?
is the fan always on?
when did you ( or someone else ) last clean it?

I recently pulled a virtual tonne of 'fluff n dust' from the heatsink/fan in my laptop and temps went from 80 - 100 ( idle - load ) to 35 - 60 ( idle - load )

and the fan doesn't scream any more

I have no idea why I left it so long

The laptop is brand new, only 1-2 months old. It is HP G6 2298SE:
https://www.google.com.pk/#q=hp+g6+2298se

About fan, I have no idea that whether it runs all the time or not. I can guess that the fan turns on when the laptop gets too hot as sometimes it feels that there some sound inside the laptop. Should the fan always on?

if brand new, should not be a dust problem

then fan shouldn't be on all the time, at least not at full speed.

pay attention to what andrewthomas says about ventilation

examine the laptop and make sure all the vents are kept clear, including those on the base
despite the name, laptops are not really for the lap in fact it is usual for manufactures to call them notebooks.

if you have air intakes on the base, then it should rest on a solid, flat service
You can get 'rests' , like a cushion with a hard top, designed for use with notebooks/laptops

If you still have heat problems , even on solid,flat surface it may be indicative of a fault
having said that, going off your google link you are in a hot climate
I think a 'higher' running temperature is to be expected

ask around, what kind of temperatures do friends and family have?

This laptop features an Intel Core i5 from the Sandybridge generation. In this case it may help to set your power-saving governor from ondemand to performance. Sounds counterproductive at first, but in the current state the ondemand governor does not support the newer Core iX CPUs correctly. Also, blocking the radeon driver does not necessarily mean that the AMD videochip is disabled properly, see if you have a BIOS option to do that, if not, try it with installing the proprietary AMD driver and disable that chip in its configuration.

Possibly poorly applied thermal grease? Too much can act as an insulator instead of a heat conduction medium.

Mass production models come with silicon based often badly applied thermal paste from the factory, use this guide as a reference if you wish to try applying your own correctly http://benchmarkreviews.com/206/best...ds/?cbg_tz=300

If the laptop has ventilation vents on the bottom, do not set it on your lap, despite the term "laptop," they aren't designed to be used in that way. It blocks the cooling system.

Get something flat to rest it on. You can find "lap desks" just for this purpose quite easily; some of them even come with "cooling pads," though I have no experience with them.

Go with TobiSGD suggestion and see if that helps first.

BIOS does not have any option to disable. However, I have installed ATI proprietary driver, and disabled ATI from CCC. Now it seemed to be solved as now temperature is 56 degree centigrade.
But only time will tell the whether it is acutllay solved or not!