Well, Microsoft come out with such a brilliant technology which is called Superfetch. It is first introduced in Windows Vista, and it is the main culprit that your RAM are fully loaded.

The main problem is cause is when you try to wake up your machine from sleep (especially if you are using a netbook), it will take forever to wake up and having you staring at the blank screen and wonder "wtf is going on?".

So, instead of calling it Superfetch, I'm calling it "Stupidfetch".

Now, how to disable it? Below are the steps:

1. Go to Windows Control Panel (Classic View) ->  Administrative Tools -> Services

2. Scroll down until you see Superfetch

3. double click on Superfetch

4. Change "Startup Type" to "Disabled"

5. Reboot your machine

Done.