No definitely not the ram. Well it could be the ram if the ram is defective, but if the ram is fine, then trust me it isn't. I had to send my two sticks of ram back because they were messed up, in the meantime I was using my sister's old computer's ram stick which was 256MB DDR266 PC-2100, even worse than yours, and I was able to play CSS with a little lag every so often and it kind of held my graphics card back (forced me to do mostly medium settings), but it still ran fine. So it probably isn't the ram, but can you explain the freezing a little more. Like what exactly happens, you're playing and then the game freezes and you need to close it or what?