2nd ram stick not used!!

Hey guys, my computer has 4gb of ram installed but only 2gb of them are used!Please help me with that i can't do my work with only 2gb used..

Welcome 654

Please provide us your complete Computer Specs also mention how and when the problem started. Does the 4GB RAM working before or you have newly installed it? Also if you are using 32bit version of Windows so it has limitations and you cannot utilize all 4GB but still in your case the RAM should show some figure around 3.5GB usable instead of 2GB alone. Let us know the above required information so we'll be able to help you.