I upgraded my Ubuntu 11.04 to 11.10 and my Wifi has stopped working. I have a Lenovo Z560 that has Intel centrino wireless-N 1000. I have searched various threads having similar problems for a solution and have no success. The wlan0 is not even showing up in rfkill. Please help me find a solution.

I am giving below the output of various debug commands. Thanks in advance.

DISTRIB_ID=Ubuntu
DISTRIB_RELEASE=11.10
DISTRIB_CODENAME=oneiric
DISTRIB_DESCRIPTION="Ubuntu 11.10"

----##uname -a

Linux gurucharapathy-laptop 3.0.0-17-generic-pae #30-Ubuntu SMP Thu Mar 8 17:53:35 UTC 2012 i686 i686 i386 GNU/Linux
----##lspci -nnk | grep -iA2 net
05:00.0 Network controller [0280]: Intel Corporation Centrino Wireless-N 1000 [8086:0084]
    Subsystem: Intel Corporation Centrino Wireless-N 1000 BGN [8086:1315]
    Kernel modules: iwlagn
06:00.0 Ethernet controller [0200]: Realtek Semiconductor Co., Ltd. RTL8101E/RTL8102E PCI Express Fast Ethernet controller [10ec:8136] (rev 02)
    Subsystem: Lenovo Device [17aa:392e]
    Kernel driver in use: r8169

----##iwconfig

lo        no wireless extensions.

eth0      no wireless extensions.

----##iwlist scan

lo        Interface doesn't support scanning.

eth0      Interface doesn't support scanning.

----##rfkill list all

0: hci0: Bluetooth
    Soft blocked: no
    Hard blocked: no
1: ideapad_wlan: Wireless LAN
    Soft blocked: no
    Hard blocked: no
2: ideapad_bluetooth: Bluetooth
    Soft blocked: no
    Hard blocked: no

----##lsmod

Module                  Size  Used by
rfcomm                 38408  8 
bnep                   17923  2 
parport_pc             32114  0 
ppdev                  12849  0 
binfmt_misc            17292  1 
snd_hda_codec_hdmi     31426  1 
snd_hda_codec_conexant    52460  1 
uvcvideo               67271  0 
videodev               85626  1 uvcvideo
snd_hda_intel          28358  2 
snd_hda_codec          91859  3 snd_hda_codec_hdmi,snd_hda_codec_conexant,snd_hda_intel
snd_hwdep              13276  1 snd_hda_codec
joydev                 17393  0 
snd_pcm                80435  3 snd_hda_codec_hdmi,snd_hda_intel,snd_hda_codec
snd_seq_midi           13132  0 
i915                  509554  9 
drm_kms_helper         32889  1 i915
snd_rawmidi            25241  1 snd_seq_midi
snd_seq_midi_event     14475  1 snd_seq_midi
snd_seq                51567  2 snd_seq_midi,snd_seq_midi_event
snd_timer              28932  2 snd_pcm,snd_seq
drm                   196290  5 i915,drm_kms_helper
snd_seq_device         14172  3 snd_seq_midi,snd_rawmidi,snd_seq
mei                    36466  0 
mac80211              393421  0 
snd                    55902  14 snd_hda_codec_hdmi,snd_hda_codec_conexant,snd_hda_intel,snd_hda_codec,snd_hwdep,snd_pcm,snd_rawmidi,snd_seq,snd_timer,snd_seq_device
ideapad_laptop         13575  0 
intel_ips              17753  0 
btusb                  18160  2 
i2c_algo_bit           13199  1 i915
soundcore              12600  1 snd
bluetooth             148839  23 rfcomm,bnep,btusb
cfg80211              172427  1 mac80211
psmouse                63474  0 
serio_raw              12990  0 
snd_page_alloc         14108  2 snd_hda_intel,snd_pcm
sparse_keymap          13658  1 ideapad_laptop
wmi                    18744  0 
video                  18908  1 i915
lp                     17455  0 
parport                40930  3 parport_pc,ppdev,lp
ahci                   21634  2 
libahci                25761  1 ahci
r8169                  47200  0 

----##nm-tool

NetworkManager Tool

State: asleep

Device: eth0 -----------------------------------------------------------------

  Type:              Wired
  Driver:            r8169
  State:             unmanaged
  Default:           no
  HW Address:        88:AE:1D:DE:5F:9C

  Capabilities:
    Carrier Detect:  yes
    Speed:           100 Mb/s

  Wired Properties
    Carrier:         on

----##lshw -C network

  *-network UNCLAIMED
       description: Network controller
       product: Centrino Wireless-N 1000
       vendor: Intel Corporation
       physical id: 0
       bus info: pci@0000:05:00.0
       version: 00
       width: 64 bits
       clock: 33MHz
       capabilities: pm msi pciexpress bus_master cap_list
       configuration: latency=0
       resources: memory:d6400000-d6401fff
  *-network
       description: Ethernet interface
       product: RTL8101E/RTL8102E PCI Express Fast Ethernet controller
       vendor: Realtek Semiconductor Co., Ltd.
       physical id: 0
       bus info: pci@0000:06:00.0
       logical name: eth0
       version: 02
       serial: 88:ae:1d:de:5f:9c
       size: 100Mbit/s
       capacity: 100Mbit/s
       width: 64 bits
       clock: 33MHz
       capabilities: pm msi pciexpress msix vpd bus_master cap_list rom ethernet physical tp mii 10bt 10bt-fd 100bt 100bt-fd autonegotiation
       configuration: autonegotiation=on broadcast=yes driver=r8169 driverversion=2.3LK-NAPI duplex=full firmware=N/A ip=192.168.0.100 latency=0 link=yes multicast=yes port=MII speed=100Mbit/s
       resources: irq:41 ioport:2000(size=256) memory:d2410000-d2410fff memory:d2400000-d240ffff memory:d2420000-d243ffff