Realtek RTL8168 drops ethernet connection

I have a Vostro1520 with a Realtek RTL8168D/8111 D Family PCI-E GBE NIC ethernet card.  It connects to my network and can get out to the internet, but after a few minutes, the connection indicates the machine is still connected to the network but I no longer have internet access.  I have to disable the card and then enable the card after which time the WEB is again accessible for a few minutes at which time it repeats.  The same thing happens if I use the Dell wireless 1510 Wireless-N WLAN Minicard for the connection.  Again I have to disable and then enable and reconnect.  I realize that this sounds like a dropped IP address, but I have 6 other computers on the network, some wIFI and some ethernet and none of them drop IP addresses.  I have update the software per MS Updater.  Any suggestions?