Have you tried hooking your system up to an external monitor to see it also shows a bad/blank screen? Is your system freezing or shutting down. Please tell us more about what your laptop is doing or not doing. More than a bad video chip can cause no video on a laptop display.
Those chips don't have pins they have pads. I would give up the notion of replacing it unless you already own a reball station. A good reball station and chip are going to cost you more than board replacement. Besides the only way to get the chip is used. The cheapest way to get it is to buy a broken laptop with the chip and remove it yourself. No programming is necessary to replace the chip.
However you have not mentioned any thoughts or attempts at reflowing the BGA for the chip. The chances are the chip itself is not bad. More than likely it is actually the balls of solder between it and the board have worked loose. If I had the equipment necessary to replace the chip I would attempt to reflow the BGA first. Please do some research on the success rate of reflowing the chip. Please hook up an external monitor to the laptop to solidify if your blank screen is caused by the chip. If an external monitor has a good picture it is not the chip.