The port on the back of the PC usually is illuminated when active. Does it go dark when the disconnect happens? Do you have more than one Ethernet port and have you tried connecting to it? When you check in device manager/network adapters; does it show any errors when the disconnect happens? When checking the network device in Device Manager, right click on it and check the power management options. Un-check any of the boxes if they are checked. If any were checked, after changing re-boot and see if that helped. Do you use a router or connect directly to an ISP modem? If you use a router try connecting directly to the modem and see if it makes a difference. Please post your hardware brands and model numbers. What does the wall connection connect to, is this a dormitory?