Is it a old ide hard drive or is it sata ? If it's ide you need to hook it to the connector that isn't master and also set the pins on the drive as non-master. If it's sata, are you plugging it in to sata port 2 through 6 and not sata port 1. Your hard drive/ssd that was in the pc when you got it need's to be in sata port 1. Look at your manuals that came with the pc or download them with another pc and read them. Also did you use a anti-static strap or ground yourself before touching anything inside the pc's case ? If none of this is wrong, then most likely you need to format the old drives. XP is different from 8. Alot of older XP pc's used Fat32, Vista and later switched to NTFS formatting. Now only flash/thumb/pen drives use FAT32, everything else uses eirher NTFS or the newer formatting for drives over 2.1 gbs. I forget what that one's called, but it start's with a g.