The specifications for your motherboard indicate it only supports a maximum of 1GB per socket.
http://www.gigabyte.com.tw/Products/...me=GA-VM800PMC
For the majority of boards, you have to fill all sockets to reach the maximum. On your board with two DDR2 sockets, 1GB per socket is the max.
Although your exact board is not listed, Kingston does have the GA-8VM800PMD-775 listed on their configurator. It has almost the exact same chipset and supports the same memory as yours.
http://www.ec.kingston.com/ecom/conf...submit1=Search
Do a Google search for the area you are in using the recommended the part numbers you are interested in to find a reseller you can buy from.
Kingston Tech Support