How to re-install Win XP on Compaq Presario R5412X

I have a Compaq Presario R5412X which I had to wipe hard drive and now I need to re-install the OS..I did not wipe the drive with the factory image but I can’t get to it…when I boot up, it is giving a msg of ” Missing OS” What can I do to re-install Windows? Pc does not have recovery disk!!! Pls help!!!!