I have a Dell D820 with the original internal modem installed, but it can't be detected. I swapped the hard drive and modem from an identical D820 in which the internal modem was working just fine and it still can't detect the modem in this one. In the device manager it gives the proper description of the modem, but it says that it has been removed. Could it be a BIOS problem? Otherwise I'm thinking a bad socket on the motherboard.