Notebook

I have been using my Dell laptop with Ubuntu 8.04 for several months now. No problems until 2 days ago when the wifi stopped working.
It's not a problem with the router, as I'm posting this with my other laptop running Windows XP, and the wireless connection works fine.
I think the problem is with the wireless being 'disabled by HW RF Kill switch', but I don't know how to solve this problem. Please help!

Here's more info:
1 ) Machine Brand and Model (PC/Laptop)
Dell Inspiron 1525 Laptop
2 ) Wireless Brand, Model and Wireless Chipset:
heng@dell-desktop:~$ lspci | grep -i 'wireless'
0b:00.0 Network controller: Intel Corporation PRO/Wireless 3945ABG Network Connection (rev 02)
3 ) check interface:
heng@dell-desktop:~$ iwconfig
lo no wireless extensions.
eth0 no wireless extensions.
wmaster0 no wireless extensions.
wlan0 IEEE 802.11abg ESSID:'
Mode:Managed Frequency:2.412 GHz Access Point: Not-Associated
Tx-Power=0 dBm
Retry min limit:7 RTS thrff Fragment thr=2352 B
Link Quality:0 Signal level:0 Noise level:0
Rx invalid nwid:0 Rx invalid crypt:0 Rx invalid frag:0
Tx excessive retries:0 Invalid misc:0 Missed beacon:0
ppp0 no wireless extensions.
4 ) Check for modules:
heng@dell-desktop:~$ lsmod | grep 'iwl'
iwl3945 96244 0
lbm_iwl_mac80211 242292 1 iwl3945
rfkill 8596 2 iwl3945
led_class 6020 1 iwl3945
lbm_iwl_cfg80211 33248 2 iwl3945,lbm_iwl_mac80211
5 ) Kernel boot messages
heng@dell-desktop:~$ dmesg | grep 'iwl'
[ 23.921723] iwl3945: Intel(R) PRO/Wireless 3945ABG/BG Network Connection driver for Linux, 1.2.26k
[ 23.921727] iwl3945: Copyright(c) 2003-2008 Intel Corporation
[ 25.932766] iwl3945: Detected Intel Wireless WiFi Link 3945ABG
[ 26.019336] iwl3945: Tunable channels: 13 802.11bg, 23 802.11a channels
[ 26.020495] phy0: Selected rate control algorithm 'iwl-3945-rs'
[ 33.729904] iwl3945: Radio disabled by HW RF Kill switch
6 ) Network configuration
heng@dell-desktop:~$ sudo lshw -C network
[sudo] password for heng:
*-network
description: Ethernet interface
product: 88E8040 PCI-E Fast Ethernet Controller
vendor: Marvell Technology Group Ltd.
physical id: 0
bus info: pci@0000:09:00.0
logical name: eth0
version: 12
serial: 00:21:9b:cc:e5:39
capacity: 100MB/s
width: 64 bits
clock: 33MHz
capabilities: pm msi pciexpress bus_master cap_list ethernet physical tp 10bt 10bt-fd 100bt 100bt-fd autonegotiation
configuration: autonegotiation=on broadcast=yes driver=sky2 driverversion=1.20 firmware=N/A latency=0 link=no module=sky2 multicast=yes port=twisted pair
*-network DISABLED
description: Wireless interface
product: PRO/Wireless 3945ABG Network Connection
vendor: Intel Corporation
physical id: 0
bus info: pci@0000:0b:00.0
logical name: wmaster0
version: 02
serial: 00:1f:3c:86:db:6c
width: 32 bits
clock: 33MHz
capabilities: pm msi pciexpress cap_list logical ethernet physical wireless
configuration: broadcast=yes driver=iwl3945 latency=0 module=iwl3945 multicast=yes wireless=IEEE 802.11abg
7 ) Network configuration:
heng@dell-desktop:~$ iwlist scan
lo Interface doesn't support scanning.
eth0 Interface doesn't support scanning.
wmaster0 Interface doesn't support scanning.
wlan0 No scan results
8 ) Ubuntu Version:
heng@dell-desktop:~$ lsb_release -d
Description: Ubuntu 8.04.2
9 ) Kernel/architecture:
heng@dell-desktop:~$ uname -mr
2.6.24-23-generic i686
10 ) Restarting the network:
heng@dell-desktop:~$ sudo /etc/init.d/networking restart
* Reconfiguring network interfaces... [ OK ]