working wireless card stopped working on previously working wireless Ubuntu 11.04

[Colin Law]

On 15 January 2012 14:10, Abhishek Dixit <abhidixit87 at gmail.com> wrote:
> On Sun, Jan 15, 2012 at 4:40 PM, Colin Law <clanlaw at googlemail.com> wrote:
>> On 15 January 2012 04:04, Abhishek Dixit <abhidixit87 at gmail.com> wrote:
>>> I have a Dell Laptop on which wireless and every thing used to work
>>> perfectly.Today morning I noticed the suddenly there is no wireless at
>>> all. On a working condition I used to have folllowing
>>>
>>> lspci -vnn
>>>
>>> 0c:00.0 Network controller [0280]: Broadcom Corporation BCM4312
>>> 802.11b/g LP-PHY [14e4:4315] (rev 01)
>>>    Subsystem: Dell Wireless 1397 WLAN Mini-Card [1028:000c]
>>>    Flags: bus master, fast devsel, latency 0, IRQ 17
>>>    Memory at f69fc000 (64-bit, non-prefetchable) [size=16K]
>>>    Capabilities: <access denied>
>>>    Kernel driver in use: wl
>>>    Kernel modules: wl, ssb
>>> and
>>>
>>> /etc/lsb-release
>>> Ubuntu 11.04 64 bit
>>> Module in use was wl.ko But now all of a sudden it fails to load any
>>> module for wireless.I have no idea why this happened.I am a SOHO user
>>> who does not have any thing other than web surfing and multimedia to
>>> do on this machine.I even booted from a Live USB but still wireless
>>> here failed to work (prior to installation same Live USB was able to
>>> detect the wifi card and wireless worked with this live USB). The
>>> driver in use was found on the LIVE cd at following location
>>>
>>> pool/restricted/b/bcmwl/bcmwl-kernel-source_5.100.82.38+bdcom-0ubuntu3_amd64.deb
>>> which used to show as additional drivers available for
>>> installation.Now this option even does not come when I boot with this
>>> Live USB.Since the installation of Ubuntu I have kept this Live USB as
>>> a backup. Can some one help here?
>>
>> If it no longer works with the live USB, but used to, and you have not
>> changed anything on the USB stick then it must be a change on the
>> laptop hardware or bios.  I presume that if there is a hardware switch
>> that it is switched on.  Check in the BIOS settings that it has not
>> got switched off there.  Is it setup for dual boot with windows?  If
>> so does it work there?
>>
> It is not a dual boot system.There is only Ubuntu 11.04 now I
> formatted it completely with 11.10 but the same situation persists.

That is not surprising given that it no longer works with the Live
USB, so it is something on the laptop that has changed or broken.  You
didn't answer the other issues.
Is there a hardware switch for the wifi.
Have you checked in the BIOS to see if anything there mentions wifi?

Colin