How to Disable Sleep Mode on a Network Card
Network cards enable a computer to connect to other computers and devices using Ethernet standards. Different protocols can run on top of Ethernet, though the primary protocol used in most networks is TCP/IP for Internet connectivity. Some Ethernet cards have different automatic power settings available in an attempt to save energy. In some cases, these low-power settings, such as sleep mode, interfere with other devices on the network or the computer itself. You can disable sleep mode on the network card to negate this issue.
Click "Start" in the lower-left corner of the desktop.
Right-click "Computer," then click "Manage."
Click "Device Manager."
Click the "+" to the left of "Network adapters" to expand the category.
Double-click the network adapter for which sleep mode is to be disabled.
Click the "Advanced" tab.
Click "Sleep Mode" or "Power Settings" or "Green LAN," depending on the model of your network adapter. Some network adapters do not have a sleep mode or equivalent setting.
Click "Disabled" under "Value."
Click "OK" to save and apply the settings.