I'd check the Compaq website (Compaq US - Presario Notebook and Laptop PCs, Desktop Computers and Accessories.).
Don't be alarmed if you get redirected to the HP web site - HP own Compaq.
I have compaq system. I bought it before 5 yrs. At that time I was not knowing much about the systems. I didnt get any disc containing drivers of my pc. I had formatted it before some months. But I didnt had drivers. I installed a common realtek audio driver so audio is working but dont have any other drivers. So from where can I get it on net?