Some testing questions/suggestions:
Does wired still work?
Try creating a new user and testing under the new user to see whether the problem is global or isolated to that one user.
Please post the output of this command, making sure to enclose them in "code" tags, which become available when you click "Go Advanced" down there at the bottom of the Quick Reply window; that makes it easier to read.
Also, please post the contents of the /etc/network/interfaces file, also surrounding it with "code" tags.
This should help get the troubleshooting started.