My friend has been running Ubuntu 11.10 for quite some time. Everything had been working fine.

The laptop shut down because of battery and when rebooted, the wireless lan hasn't been working with a message "Wireless is disabled by hardware switch". He has checked that the hardware switch is indeed on.

The output of rfkill list is as follows:

 0: ideapad_wlan: Wireless LAN

    Soft blocked: no

    Hard blocked: no

 1: phy0: Wireless LAN

    Soft blocked: no

    Hard blocked: yes

 2: ideapad_bluetooth: Bluetooth

    Soft blocked: no

    Hard blocked: no

He even tried rfkill unblock all but rfkill list still showed Hard blocked: yes for phy0: Wireless LAN.

Following is the description of wireless interface returned by lshw:

 *-network DISABLED

   description: Wireless interface

   product: Centrino Wireless-N 1000

   vendor: Intel Corporation

   physical id: 0

   bus info: pci@0000:06:00.0

   logical name: wlan1

   version: 00

   serial: 74:e5:0b:0c:39:0e

   width: 64 bits

   clock: 33MHz

   capabilities: pm msi pciexpress bus_master cap_list ethernet physical wireless

   configuration: broadcast=yes driver=iwlagn driverversion=3.0.0-14-generic-pae firmware=128.50.3.1 build 13488 latency=0 link=no multicast=yes wireless=IEEE 802.11bgn

   resources: irq:42 memory:e8100000-e8101fff

Just for the info, my friend doesn't have Windows on his machine.