Intel integrated graphics card (with laptop chipset at that) is definitely not for gaming.
Keep in mind that the original L4D used older engine while both L4D2 and Alien Swarm use Valve's newer engines. Your graphics card probably won't be able to run it smoothly in any case. It was the same with my desktop intel chipset; I would get stable 30< frames in L4D while L4D2 was basically a slideshow.
Back to the topic, RAM is enough while CPU probably pass over bare minimum. The problem might be the softwares such as DirectX, PhysX, etc, or it could be the video card itself, although I don't think that's the case here. Make sure the softwares are updated. Is the problem happening only on the later Valve games or does the same thing occur on other newer games?
Edit:
well we know from what you've posted so far that your CPU and Memory can handle the game, but we need to know what the graphics card is, if the computer has 3gig of ram though from purchase it's probably pretty safe to say that the graphics card should be able to handle l4d2 or alien storm even on the lowest settings >_
Laptops with 3 gigs is placed in low-mid quartile for gaming purposes. Trying to play any games after 2006~07 with any integrated chipsets (unless they are of Radeon or Geforce) would probably result in really, REALLY laggy gameplay (speaking from experience)