Macbook white ram issue...

Hello hello!

Yesterday i made the switch and brought my first macbook white. I installed snow leopard on it and all was well.
Ive got a few apps installed on it and today while checking the activity monitor i noticed it said i only had 250mb ram left. Thats almost 4gb used and all i had open was adium and ical. I checked the activity monitor again and looked at what was running and there was barley anything - and adium was only using like 45mb as was ical.

Does anyone know where the **** this 3.7gb has gone? Ive tried rebooting but the same thing just happens after like half an hour... And as you can guess, its slowing everything down.

Specs - 2009 Macbook white. 2.13ghz duel core - 4gb ram - 250gb hdd.

Thank you in advance!

Mike

Go to about this mac top left apple. Does it state the proper ram. When using activity monitor are you checking all ( not my) processes. If not change it. Also, what are your inactive processes and wired showing. Remember your computer will use the ram it has to be efficient. We need know the above info first.