Did u install the correct drivers for your Motherboard ???
Im no pro in these matters...but if i dont install some SATA drivers for my Mobo...my SATA driver is not recognized by Windows XP :S
Also once replacing the drivers which were given to me by the mobo CD...i installed some USB 2.0 drivers to my PC (downloaded using some software)....and blv me the USB speed sooooooooooo bad!!!
It took me like 3 or 4 hours to get a 700 MB file from an external HDD in to my PC.
So all i can say is...did u install the drivers from your Mobo CD....and are they the correct ones???? Give a try updating to the latest SATA drivers from the vendors website...might help
Maybe this might sound "LOL" for you'll

...but all i can help is this way