Recently I have upgraded my OS from 12.10 to 13.04, its working just fine.
I was not facing this problem till today but I am not able to connect to a particular WiFi from the morning. I have two WiFi here & I am able to connect to other one.
As for the WiFi, there is no issue as other persons who are using Window can connect with that just fine. How to resolve this problem I don't know?
Note - I have restarted the WiFi as well as the system two times to overcome this issue.
Edited for giving more info:
[full lspci output can be found in revision 2 of this post] .... 04:00.0 Network controller: Intel Corporation WiFi Link 5100 09:00.0 Ethernet controller: Realtek Semiconductor Co., Ltd. RTL8111/8168 PCI Express Gigabit Ethernet controller (rev 03) ....
sudo lshw -c network
*-network description: Wireless interface product: WiFi Link 5100 vendor: Intel Corporation physical id: 0 bus info: pci@0000:04:00.0 logical name: wlan0 version: 00 serial: 00:24:d6:43:c0:58 width: 64 bits clock: 33MHz capabilities: pm msi pciexpress bus_master cap_list ethernet physical wireless configuration: broadcast=yes driver=iwlwifi driverversion=3.8.0-25-generic firmware=184.108.40.206 build 33692 ip=192.168.1.17 latency=0 link=yes multicast=yes wireless=IEEE 802.11abgn resources: irq:44 memory:f0500000-f0501fff *-network DISABLED description: Ethernet interface product: RTL8111/8168 PCI Express Gigabit Ethernet controller vendor: Realtek Semiconductor Co., Ltd. physical id: 0 bus info: pci@0000:09:00.0 logical name: eth0 version: 03 serial: b8:ac:6f:68:08:6d size: 10Mbit/s capacity: 1Gbit/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 1000bt 1000bt-fd autonegotiation configuration: autonegotiation=on broadcast=yes driver=r8169 driverversion=2.3LK-NAPI duplex=half firmware=rtl_nic/rtl8168d-1.fw latency=0 link=no multicast=yes port=MII speed=10Mbit/s resources: irq:41 ioport:5000(size=256) memory:f0404000-f0404fff memory:f0400000-f0403fff memory:f0420000-f043ffff
[ 2244.563918] wlan0: authenticate with 00:25:5e:17:6b:28 [ 2244.566162] wlan0: send auth to 00:25:5e:17:6b:28 (try 1/3) [ 2244.768488] wlan0: send auth to 00:25:5e:17:6b:28 (try 2/3) [ 2244.972143] wlan0: send auth to 00:25:5e:17:6b:28 (try 3/3) [ 2245.175754] wlan0: authentication with 00:25:5e:17:6b:28 timed out [ 2264.745062] wlan0: authenticate with 00:25:5e:17:6b:28 [ 2264.746376] wlan0: direct probe to 00:25:5e:17:6b:28 (try 1/3) [ 2264.949654] wlan0: direct probe to 00:25:5e:17:6b:28 (try 2/3) [ 2265.153340] wlan0: direct probe to 00:25:5e:17:6b:28 (try 3/3) [ 2265.356923] wlan0: authentication with 00:25:5e:17:6b:28 timed out