In my situation i had 3 gb's Rams are usable of 4 existing ones...
There are 2 method how to solve it:
- Install windows with 64 bit. ( Need one? get it from amazon )
- Other easier trick:
1. You need to find on internet small and neat program which was created by Russian programmers which is called "4GB-RAMPatch". ( From my dropbox )
2. Run it, and press "Patch x86 Ramlock".
* After you patch, you will be able to start windows in 2 different boots. first - with increased rams, and second is normal one.. You can change "waiting time" in start->run->msconfig ( boot tab ).
After you boot small text will appear near clock "Test mode". But i guess you can try to remove if you don't like it a lot. I'm lazy, so 'ill leave it alone for now..
Anyways you can unpatch anytime.