Wrong 240-pin memory?

You bought DDR3 ram instead of DDR2 which your motherboard supports. DDR3 runs at a higher frequency, different timings, and different voltages. Send it back and buy some DDR2 800mhz ram because thats what your board supports.
 
Ahhh! Thank you all for the great replys. I see that DDR2 is a little more expensive but seems runs a little quicker. Anyways, thanks again! I hope I never make that mistake again :).