I'm connected to my wireless network but am unable to connect to the internet. It appears I do not have an IP address and I'm not sure what to do. I had working internet until I booted up this morning. What is the best way to fix this in Ubuntu 10.04
I know it sounds dumb, and I am by no means an expert, but have you tried resetting your computer or router? Also, have you tried the new LTS release 12.04? You can try it via a live usb and see if it fixes your issue. If so, you may want to consider upgrading. Furthermore, did you install any programs or updates before you last shutdown the computer?
I know the above sounds like your standard IT suggestions, and are perhaps obvious, but if you haven't tried them you may be pleasantly surprised. In my experience as an "average user" (with limited command line knowledge), often a simple restart fixes the problem. Also, try reconnecting to the network and pining sites to "force" an internet reconnection.
Things to try...
Put your laptop on wall power.
Does the laptop have a wireless kill switch? Switch it on. Still doesn't work? Reboot.
Enter BIOS setup and make sure the Wi-Fi interface is still enabled.