Yes that memory should work you just need to make sure that you buy it in pairs, so if you want to add 1 gb of ram then you need to get 2 sticks of 512mb and not a single 1gb stick or if you like get two 1gb sticks. Otherwise if you add only one stick your computer won't run in dual channel any more and your performance will drop a lot. Your computer should have two 512mb sticks now and just add the two new 512mb sticks to the open slots. Non ecc is what you want anyway so you should be good there.