My Asus K40IN hangs after a ram upgrade was installed, how do I fix this?

My Asus K40IN hangs after a ram upgrade was installed, how do I fix this?

From a 2GB RAM I upgraded the K40IN and added another ram to make it into 4GB. what happens is it hangs a lot. Especially right when I boot/startup the laptop. Would updating the resolve this problem, if it does how do I update the bios?