Wireless Disappeared

Hi,
I have a hp probook 4431s running ubuntu 12.04.
The wifi was running fine.
But after shutting down, when I booted the laptop, before starting ubuntu it flashes the message that wireless module disabled. Wireless module id 702.
After booting the wireless icon has disappeared. I executed rfkill unblock all. Even the light of wifi button still glows white. If I physically press the button even then it does not turn amber.

 cso@cso-HP-ProBook-4431s:~$ rfkill list
0: hp-wifi: Wireless LAN
 Soft blocked: no
 Hard blocked: no

output of lshw

 *-network
                description: Ethernet interface
                product: RTL8111/8168B PCI Express Gigabit Ethernet controller
                vendor: Realtek Semiconductor Co., Ltd.
                physical id: 0
                bus info: pci@0000:26:00.0
                logical name: eth0
                version: 06
                serial: e4:11:5b:54:b3:bc
                size: 100Mbit/s
                capacity: 1Gbit/s
                width: 64 bits
                clock: 33MHz
                capabilities: pm msi pciexpress msix vpd bus_master cap_list ethernet physical tp mii 10bt 10bt-fd 100bt 100bt-fd 1000bt 1000bt-fd autonegotiation
                configuration: autonegotiation=on broadcast=yes driver=r8169 driverversion=2.3LK-NAPI duplex=full firmware=rtl_nic/rtl8168e-2.fw ip=192.168.1.176 latency=0 link=yes multicast=yes port=MII speed=100Mbit/s
                resources: irq:52 ioport:2000(size=256) memory:a4404000-a4404fff memory:a4400000-a4403fff

output of lspci

cso@cso-HP-ProBook-4431s:~$ lspci
00:00.0 Host bridge: Intel Corporation 2nd Generation Core Processor Family DRAM Controller (rev 09)
00:01.0 PCI bridge: Intel Corporation Xeon E3-1200/2nd Generation Core Processor Family PCI Express Root Port (rev 09)
00:02.0 VGA compatible controller: Intel Corporation 2nd Generation Core Processor Family Integrated Graphics Controller (rev 09)
00:16.0 Communication controller: Intel Corporation 6 Series/C200 Series Chipset Family MEI Controller #1 (rev 04)
00:1a.0 USB controller: Intel Corporation 6 Series/C200 Series Chipset Family USB Enhanced Host Controller #2 (rev 04)
00:1b.0 Audio device: Intel Corporation 6 Series/C200 Series Chipset Family High Definition Audio Controller (rev 04)
00:1c.0 PCI bridge: Intel Corporation 6 Series/C200 Series Chipset Family PCI Express Root Port 1 (rev b4)
00:1c.1 PCI bridge: Intel Corporation 6 Series/C200 Series Chipset Family PCI Express Root Port 2 (rev b4)
00:1c.2 PCI bridge: Intel Corporation 6 Series/C200 Series Chipset Family PCI Express Root Port 3 (rev b4)
00:1c.5 PCI bridge: Intel Corporation 6 Series/C200 Series Chipset Family PCI Express Root Port 6 (rev b4)
00:1c.7 PCI bridge: Intel Corporation 6 Series/C200 Series Chipset Family PCI Express Root Port 8 (rev b4)
00:1d.0 USB controller: Intel Corporation 6 Series/C200 Series Chipset Family USB Enhanced Host Controller #1 (rev 04)
00:1f.0 ISA bridge: Intel Corporation HM65 Express Chipset Family LPC Controller (rev 04)
00:1f.2 SATA controller: Intel Corporation 6 Series/C200 Series Chipset Family 6 port SATA AHCI Controller (rev 04)
01:00.0 VGA compatible controller: Advanced Micro Devices [AMD] nee ATI Seymour [Radeon HD 6400M Series]
24:00.0 System peripheral: JMicron Technology Corp. SD/MMC Host Controller (rev 30)
24:00.2 SD Host controller: JMicron Technology Corp. Standard SD Host Controller (rev 30)
24:00.3 System peripheral: JMicron Technology Corp. MS Host Controller (rev 30)
26:00.0 Ethernet controller: Realtek Semiconductor Co., Ltd. RTL8111/8168B PCI Express Gigabit Ethernet controller (rev 06)
27:00.0 USB controller: NEC Corporation uPD720200 USB 3.0 Host Controller (rev 04)

cso@cso-HP-ProBook-4431s:~$ iwconfig
lo no wireless extensions.

eth0 no wireless extensions.

How to get wif back?