Okay I did a little research into your motherboard. It looks like it can only handle 1GB per slot. This means that there is no way yo fix this issue without buying more ram. I recommend two of this ram from newegg
. It has the exact same specs as your previous ram. I wouldn't recommend using 667fsb ram unless you were going to replace the older sticks in addition to getting new ones. I also would look into if you could return the 2GB stick to where ever you got it from if I were you. If not, sell/give it to someone you know. It would suck for you to be out $40-50 on the ram you already bought.