Also affects HP 4740s notebook. But in my case step #8 solved problem until reboot and then i got "Wireless networks: device not ready" message in the connections popup window.

This is my config:

uname -a==============================================
Linux dmishh-hp 3.6.11-030611-generic #201212171335 SMP Mon Dec 17 18:36:00 UTC 2012 x86_64 x86_64 x86_64 GNU/Linux


ifconfig -a==============================================
eth0      Link encap:Ethernet  HWaddr b4:b5:2f:7d:68:c1  
          inet addr:192.168.0.102  Bcast:192.168.0.255  Mask:255.255.255.0
          inet6 addr: fe80::b6b5:2fff:fe7d:68c1/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:3307 errors:0 dropped:0 overruns:0 frame:0
          TX packets:2781 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:3278098 (3.2 MB)  TX bytes:497896 (497.8 KB)

lo        Link encap:Local Loopback  
          inet addr:127.0.0.1  Mask:255.0.0.0
          inet6 addr: ::1/128 Scope:Host
          UP LOOPBACK RUNNING  MTU:16436  Metric:1
          RX packets:1057 errors:0 dropped:0 overruns:0 frame:0
          TX packets:1057 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0 
          RX bytes:91410 (91.4 KB)  TX bytes:91410 (91.4 KB)

wlan0     Link encap:Ethernet  HWaddr 68:94:23:b7:45:1f  
          BROADCAST MULTICAST  MTU:1500  Metric:1
          RX packets:0 errors:0 dropped:0 overruns:0 frame:0
          TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:0 (0.0 B)  TX bytes:0 (0.0 B)

iwconfig==============================================
eth0      no wireless extensions.

lo        no wireless extensions.

wlan0     IEEE 802.11bgn  ESSID:off/any  
          Mode:Managed  Access Point: Not-Associated   Tx-Power=0 dBm   
          Retry  long limit:7   RTS thr:off   Fragment thr:off
          Power Management:off


sudo lshw -C network==============================================
  *-network DISABLED      
       description: Wireless interface
       product: Ralink corp.
       vendor: Ralink corp.
       physical id: 0
       bus info: pci@0000:03:00.0
       logical name: wlan0
       version: 00
       serial: 68:94:23:b7:45:1f
       width: 32 bits
       clock: 33MHz
       capabilities: pm msi pciexpress bus_master cap_list ethernet physical wireless
       configuration: broadcast=yes driver=rt2800pci driverversion=3.6.11-030611-generic firmware=0.37 latency=0 link=no multicast=yes wireless=IEEE 802.11bgn
       resources: irq:19 memory:c0610000-c061ffff
  *-network
       description: Ethernet interface
       product: RTL8111/8168B PCI Express Gigabit Ethernet controller
       vendor: Realtek Semiconductor Co., Ltd.
       physical id: 0
       bus info: pci@0000:04:00.0
       logical name: eth0
       version: 07
       serial: b4:b5:2f:7d:68:c1
       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=rtl8168e-3_0.0.4 03/27/12 ip=192.168.0.102 latency=0 link=yes multicast=yes port=MII speed=100Mbit/s
       resources: irq:46 ioport:2000(size=256) memory:c0404000-c0404fff memory:c0400000-c0403fff

Any ideas?