vancer

I have a few questions about various problems I have had with arma. I absolutely love the game, and want to submerge myself in it a little deeper. The problem is, I have yet to get it to run properly. Sometimes Arma runs great, and other times it crashes. I played last night for four hours without any problems. I went to play today and it crashed within five minutes. It just says program stopped working. It locks up my mouse and I have to go to task manager. First off I bought reinforcements, but I found out that I needed arma 2 for the more expansive multiplayer modes. This forced me to buy combined ops from sprocket. So I uninstalled reinforcements and installed the sprocket version of combined ops. System = intel ® core (im) i3 cpu 530@2.93 GHz. Installed Memory (ram) 2.00GB. 64 bit. NVIDIA GeForce GTX 550 Ti. Primary monitor resolution 1176/664. Does anyone have a solution to my problem? Is it the Sprocket version? Should I just install sprocket Arma 2 and then reinforcements to arma 2 directory? Will that still permit me to play on servers running lite versions? Is there something I need to do to optimize? I really need some help. Thanks in advance.