Error PXE-E61 / PXE-M0F and no bootable device error

Hello experts!
I am not highly developed in IT and I am looking for a number of simple suggestions. I use a Packard bell laptop which is 6 months older. It was running very fine and then it rebooted itself. At the same time as I was running it – Now I get the following error message through a white font /black screen…..
PXE-E61: Media test failure, check cable
PXE-M0F: Exiting Broadcom PXE ROM
No bootable device – insert boot disk and press any key
Do you have you any ideas? Please ask me if you require any more information.
Please help. Thanks.
