Something like this happened to me, but it was when I built a comp a little while ago, it was such a stupid mistake, you already checked the IDE channels right? If you did, take a look at the end of the cable that goes to the hard disk, you may have put it in backwards, thats what I did, I had mine upsidedown because it was an older IDE cable, and it didnt have any of the pin blocks in it so you cant really tell. that may be the case. Also are you trying to use rounded IDE cables? because if you have a regular flat one, and you round it yourself, if you dont have an electromagnetic net thing around the newly rounded cable, if you did it yourself then the currents from the wires could be screwing woith your signal.