PXE-E61: Media test failure,check cable

Today my notebook (TOSHIBA) suddently just restarted and now it won`t turn on again. This is what's on my screen at the moment: Intel UNDI, PXE-2.1 (build 082) Copyright (C) 1997-2000 Intel Corporation For Realtek RTL8100E/8101E Fast Ethernet Network Adapter v1.02 (060510) PXE-E61: Media test failure, check cable PXE-MOF: Exiting PXE ROM. Intel UNDI, PXE-2.1 (build 082) Copyright (C) 1997-2000 Intel Corporation For Realtek RTL8100E/8101E Fast Ethernet Network Adapter v1.02 (060510) PXE-E61: Media test failure, check cable PXE-MOF: Exiting PXE ROM. what should I do????