I just did a fresh install of Ubuntu 16.04 on a desktop computer. During the installer, the auto network script failed so I configured it manually (entered my own IP, entered in the subnet mast, entered in the default gateway) and everything was okay with no problems. It connected successfully and finished the install.
Now that it's installed, I'm not getting any network connectivity - I can't even ping the gateway. I'm using wifi and am unable to use ethernet. ifup/ifdown on enp2s0 doesn't have an issue. I tried with DHCP, but DHCP just hanged and didn't solve it either. I also verified the requested IP address wasn't in use on the network.
root@ubuntu:/home/liam# lshw —class network
*—network
description: Ethernet interface
product: RTL8111/8168/8411 PCI Express Gigabit Ethernet
vendor: Realtek Semiconductor Co., Ltd.
physical id: O
bus info: pci@0000:02:00.0
logical name: enp2s0
version: 06
serial: b8:97:5a:32:c1:5f
size: 10Mbit/s
capacity: 1Gbit/s
width: 64 bits
clock: 33MHz
capabilities: pm msi pciexpress msix vpd bus_master cap_list
configuration: autonegotiation=on broadcast=yes driver:r8169
resources: irq:25 ioport:d000(size=256) memory:f0004000-f000
*-network DISABLED
description: Wireless interface
physical id: 1
bus info: usb@1:2
logical name: wlxec086b1eaf1b
serial: ec:O8:6b:1e:af:1b
capabilities: ethernet physical wireless
configuration: broadcast=yes driver:r8188eu multicast=yes
Output of /etc/network/interfaces
# This file describes the network interfaces available on your system
# and how to activate them. For more information, see interfaces(5).
source /etc/network/interfaces.d/*
# The loopback network interface
auto lo
iface lo inet loopback
# The primary network interface
auto enp2s0
iface enp2s0 inet static
address 192.168.1.200
netmask 255.255.255.0
network 192.168.1.0
broadcast 192.168.1.255
gateway 192.168.1.254
# dns-* options are implemented by the resolvconf package
dns-nameservers 192.168.1.254
wpa-ssid ATT548CA
wpa-psk frank777
#auto enp2s0
#iface enp2s0 inet dhcp
# wpa-ssid ATT548CA
# wpa-psk frank777
EDIT: Wireless Info Script results: http://paste.ubuntu.com/24446060/