Upgraded 10.04 to 12.04, but wireless no longer works

[Paddy Landau]

• Standard Ubuntu installation, 10.04 64-bit, fully updated. Everything worked.
• Upgraded to 12.04 using Update Manager.
• Wireless no longer works.

I can access the Internet using an Ethernet cord, but the wireless — which worked in 10.04 — no longer works.

The screen-shot shows how the wireless cannot be enabled.
Wireless disabled.png

There is a wireless button on the machine, which (in Windows, when it used to have WIndows on the machine) would go blue when on and amber when off. However, the button has never worked in Ubuntu; it always remains blue and pressing it does nothing. (I have, of course, tried again in 12.04, with the expected non-result.)

I am clueless as to how to fix the wireless. Please help.

[Paddy Landau]

I found the solution entirely by accident!

System Settings > Network > Wireless > was turned off.

I don't know why I couldn't turn it on from the usual place.

The little wireless light also works now, albeit not as I expected: blue when idle, amber when in use.

I'll marking the thread as solved.