Just for your info, I'm beginning to think it has to be the modem. I'm making my own cables using brand new Cat 5E and crimp on's. There are no kinks as the cable is laying on my floor. I'm getting a signal but it is weak. I thought maybe the crimps were no good (even though I double check them and have redone several times using new connectors every time) so I picked up a couple of surface mount boxes with screw mounts. Figured it would insure good connections. Same deal. Drifts in and out of connected. Since it is fine with the 15' cable I'm assuming the NIC is fine.
Any other clues would be appreciated, but I think I'll call Verizon and get another modem. Thanks!