I'm trying ubuntu on an HP atom mini-laptop. I boot from a USB stick. The network is disabled and I can't get it enabled. Available wi-fi networks are not displayed. Is networking limited/restricted when trying ubuntu?
If you click on the Wireless symbol in the top right of your screen, a drop-down menu will list "Enable Networking" towards the bottom. A check mark next to it means it is enabled. From the Unity Dash you can search for "Network," select Wireless on the left, and click the Off/On Button. While you're there, also ensure Airplane Mode is Off just above it.
The Ubuntu Official Documentation and Wiki are great resources for all, but especially those just getting started. Here is the Wireless Networking Section in the Official Documentation that will more than likely have the answer you need. As belacqua commented, the bootable Ubuntu Live Session is able to connect to wireless networks the same as an installed version. If you cannot find your answer in the link above, I'd recommend posting the output of these command from terminal by editing your question:
lsb_release -a ifconfig