The computer boots up and the BIOS can recognize the primary (master/slave) hard disk drive, but it cannot recognize all devices connected to the secondary hard disk drive. Why?
Is the power connected?
Is the IDE interface cable correctly connected? (Make sure it is completely plugged in)
Is the setup correct? Is the position of the jumper pin correctly set?
In the BIOS, is the secondary disabled? (For detailed information on BIOS settings, please contact the PC's manufacturer)
Is the secondary's interface cable too long? (Has it exceeded the ATAPI specification of 18 inches/45cm?)
Is the IDE cable's pin twisted? (Also, make sure there is no reversed insertion.)