I am gonna buy a new laptop with this specs (core i5-3210M 2.5 GHZ, 6-8 GB Ram, and Video Card GT 630m or Radeon HD 7670m).
Now, this is the question: If the videocard will crash or if i wanna change the video card, can i replace it? With a better one, like GTX 660 or GTX 560-570-580 or hd 6950 or 7850 or another 1 with 256bit GDDR5... The laptop have integrated hd 4000 and dedicated gt 630m or 7670m. I am gonna chose one of two laptops. The difference is made by the video card (gt 630m or hd 7670m).
I seen on this site another questions, but a little different. I know, for the older laptops the upgrade is not possible. But the modern laptops, can be upgraded the dedicated video cards. I read an answer, and that user said "Video card upgrading it's possible but it's a little hard to do that".
It depends on the model of the laptop. Most(about +90%) are integrated and non upgradable. Others can be replaced(without replacing the entire motherboard) but are not really upgradable. Usually only the high to super high end laptops have upgradable graphics(MXM slots). If I were to guess from the information you provided I would be fairly certain the laptop you are looking at does not have upgradable graphics.
You really need to get the best laptop you can afford from the start, they are hard to upgrade if not impossible. If you can't get the video card you want and are able to wait... I would suggest waiting to buy the laptop till you have the money to get a better video card from the start.