I have a Acer Aspire 1800 series. Switched from Windows 7 to Ubuntu 12.04.New to Linux; need help, please.
Are you saying that you do have a wireless router working, and you intend to connect to the wireless network in Ubuntu 12.04? In this case you might want to check out the bar at the top of the screen; there is an icon, by clicking which you can see something like Enable Wireless Network. Make sure it's ticked and you should be able to find your network in that popup menu. Click on the network and follow the instructions!
Hit CTRL+ALT+t, then type this in:
lspci | grep -i network
Then highlight the resulting text, right-click, select copy, then paste it as a response here. This will show what type of wireless you have, and we can help getting it working from there.
Other things to check: 1.) Ensure your physical wireless switch is left in the on position when you start up. 2.) Plug in the Ethernet cable and try running the updates from the "Updates Available" menu item (4th down) on the on-screen power button in the upper r/h corner of the Ubuntu interface.