Hi.  This is the first time I've posted to the forum, so please bear with me. 

I have a six-month old Inspiron 530 which is connected online via an ethernet cable to a modem.  After working fine since I bought it, the computer suddenly does not now seem to recognise the ethernet cable, so I can't get online.  The network troubleshooter continues to say "plug an ethernet cable in"  The ethernet port at the back of the computer flashed a bit at the beginning of the problem, but now nothing.  I looked at the network properties (I have a realtek PCIe GBE family controller, supplied with the computer) and the status says it's working properly.  The modem is fine and I've tried a couple of cables with the same result.  Can anyone help please?