Assuming the Intel HD graphics core can address up to 2GB of RAM, the problem is your laptop only has 4GB of RAM. The operating system and the game needs RAM as well as the background tasks. I assume the Intel HD graphics core can use up to 2GB of RAM if the laptop has 8GB of RAM or more installed.
The question is which Intel HD graphics core do you have? They all have different performance level depending on the model. The current generation Core i3 will have either the Intel HD 4400 ("u" models) or the Intel HD 4600 ("m" models). Whle Intel HD graphics performance has come a long way in just a few years, they are still considered weak in comparison to discrete graphic chips.