my compaq presario CQ61 dual core is not rejecting playing some 3D games like Hitman(contract). have tried updating the graphics driver,but still its not responding... what should i do?
Nope. You need a dedicated graphics card made by either AMD or Nvidia. Laptops aren't customizable so you won't be able to put a better graphics card into it.
You can either buy a gaming desktop computer, buy a gaming laptop (Usually pretty expensive), buy a normal desktop computer and install a graphics card or build your own computer.
Intel graphics is just a chip soldered to the motherboard and it shares the ram your CPU uses. On some computers the graphics "chip" is built into the CPU. These kind of chips are pretty limited to what they can do. Integrated graphics are found on cheaper computers to keep the costs down. They also don't have the raw ability to process higher level graphics that a dedicated card does because. This means the games you want to play simply wont run because that chip just cant deal with the computations required to run most games. you can run simple, older games that dont require much graphics ability.
And even though some manufacturers offer laptops (the higher priced laptops) with a graphics card, they are a specialized "mobile" graphics card. These "mobile" versions are usually scaled down versions of desktop graphics cards and though they can run some games, it wont be at the best graphic levels you may want. They are scaled down to reduce costs, to be smaller to fit in the laptop, and run at lower powers to keep case temperatures down.