I believe that the problem with the flat cables is that the IDC connections themselves become flaky.? While you can attempt to re-crimp the connections, I just use 6" ribbon cable jumpers, pre-terminated on each end, as a replacement.? They are available for practically nothing on Amazon or ePay and have worked extremely well for me.? Also, the ribbon cable connecting the front panel to the motherboard often becomes loose so it is a good idea to make sure it is completely plugged in tightly on both ends if you have the case open.
Hal
Harold Foster