You need DDR 400 Ram for that MOBO - the chipset that the MOBO uses can be used on either MOBOs that support DDR or DDR2 but the MOBO you have only has DDR slots and the modules are different for each type and not interchangeable !!
Also you need to check and see if the MOBO supports dual sided modules (since it says it only supports 2GB MAX it may only support single sided modules so will not work with dual sided modules further limiting your choices !!)
I never did like Sony PCs . You're going to have to buy the more expensive DDR 400 Ram if you want 2GB