I have just bought a new 1tb Western digital sata hard drive [WD10EADS] to use as my secondary drive. It was bought to replace a 320gb sata seagate drive that i was using but is now too small. The problem i am having is that the new drive is being detected at bios start-up [ie the drive number is showing] but the system will not boot up. The system is installed and booting from a different drive however - the new drive is only for data. I have tried changing the jumper settings and the only time the system will boot up is when the jumper is on the 3,4 setting but the drive number does not come up during startup and is not accessible in 'disk manage'. The system seems to detect that a drive is there but the drive information is not shown for it and it is not accessible in windows. My motherboard is a pata system but i have a sata to ide card which worked perfectly with the segate drive. I don't understand how one works and not the other. Both drives are SATA II and have a 32mb cache so the interface is identical, just not the manufacturer. The jumper settings cannot be copied either as the segate drive uses 4pins whereas the WD one uses 8. I'm running XP home as my system. The motherboard is an AS-Rock K7S41. I have installed the hard drive on another system [with a sata motherboard] and the drive comes up properly so have established that the hard drive is ok. I also formatted the hard drive on that system to see if that would make a difference but it still isn't recognised in my own. I have successfully used the hard drive with the ide to sata controller card in a pata external hard drive enclosure [i.e. via a usb connection] so have established that the drive works with the controller. The situation now is that the hard drive works, the ide to sata controller works and the older sata drive still works but for some reason the new drive wont work in my system. Please help!