Windows 7 Two graphics card

[hackroot]

hi fellas,, First i dont know much about computers and i m complete idiot about tech stuff..
i bought HP Pavilion dv6t-3100 CTO
core i 5
6 Gb ram
and when i see system properties there are two graphics adapters listed
1: Intel HD graphics
2: Ati mobility radeon HD 5470

can anybody tell me why there are two graphics cards listed
and can i use the one which is the perfect for a game.. if yes then how to choose??
here are some other details about my graphics
one more thing i want to run GTA iv with this graphics card is it possible?

 

[powerbomb]

i5 has a built in graphics card.

 

[alberto]

You should be able to define which graphics card to use in the HP power configuration utility (I'm not sure about the name but it's most likely something similar). In theory if you're plugged in you should be using the ATI card by default when plugged into AC power and the Intel one when running on battery, but you should be able to verify and change that with the HP power utility.