Ubuntu 13.04: Ethernet works at office but not at home. DHCP issue maybe?

Ubuntu 13.04: Ethernet works at office but not at home. DHCP issue maybe?

I am fairly new to Linux and just installed Ubuntu 13.04 on an external
USB HD (using the liveCD). The computer the drive is connected to is a
Dell Precision M4500 (laptop).
After the fresh install, the wired Ethernet connection does not work when
I am at home. However, when I go into my office and connect to the wired
Ethernet network there, the wired connection does work.
The result is the same before and after the initial software updates. Also
as another note, the wireless has never worked... it shows nearby wireless
connections that are available but when I try to connect to them, I just
get an authentication prompt over and over (or at home, there is no
authentication prompt [WPA2 passcode is set], it just tries to connect and
then fails and tries again in a loop). All that to say, when I go home
later and check to see if there are answers, I will not have internet on
the Linux machine.
My best guess is that it is a DHCP issue with Ubuntu but I have no idea
where to begin. Please let me know what logs or other information is
needed to diagnose (although without internet, it's a little hard to copy
and paste).
As another note, when I boot the laptop into Windows 7, the wired
connection works fine at home (not a bad router/cable... able to obtain an
IP address, etc).
Thanks