I've got a problem with the WLN connection on Ubuntu 8.04 (same problem appeared in 7.10, before the upgrade). Sometimes at the start-up no WLAN is detected... then, apparently after no reason (for my understanding) after a e-boot the WLAN is there again. Lately I didn't manage to have it back working.
I have the feeling the W-card is not detected: it is a Gigabyte GN-WP01GT.
Further info:
iwconfig gives:
lo no wireless extensions.

eth312 no wireless extensions.

lspci:
00:00.0 Host bridge: nVidia Corporation Unknown device 07c1 (rev a2)
00:00.1 RAM memory: nVidia Corporation nForce 630i memory controller (rev a2)
00:01.0 RAM memory: nVidia Corporation nForce 630i memory controller (rev a1)
00:01.1 RAM memory: nVidia Corporation nForce 630i memory controller (rev a1)
00:01.2 RAM memory: nVidia Corporation nForce 630i memory controller (rev a1)
00:01.3 RAM memory: nVidia Corporation nForce 630i memory controller (rev a1)
00:01.4 RAM memory: nVidia Corporation nForce 630i memory controller (rev a1)
00:01.5 RAM memory: nVidia Corporation nForce 630i memory controller (rev a1)
00:01.6 RAM memory: nVidia Corporation nForce 630i memory controller (rev a1)
00:02.0 RAM memory: nVidia Corporation nForce 630i memory controller (rev a1)
00:03.0 ISA bridge: nVidia Corporation Unknown device 07d7 (rev a2)
00:03.1 SMBus: nVidia Corporation Unknown device 07d8 (rev a1)
00:03.2 RAM memory: nVidia Corporation Unknown device 07d9 (rev a1)
00:03.4 RAM memory: nVidia Corporation Unknown device 07c8 (rev a1)
00:04.0 USB Controller: nVidia Corporation GeForce 7100/nForce 630i (rev a1)
00:04.1 USB Controller: nVidia Corporation GeForce 7100/nForce 630i (rev a1)
00:08.0 IDE interface: nVidia Corporation Unknown device 056c (rev a1)
00:09.0 Audio device: nVidia Corporation MCP73 High Definition Audio (rev a1)
00:0a.0 PCI bridge: nVidia Corporation Unknown device 056d (rev a1)
00:0b.0 PCI bridge: nVidia Corporation Unknown device 056e (rev a1)
00:0c.0 PCI bridge: nVidia Corporation Unknown device 056f (rev a1)
00:0d.0 PCI bridge: nVidia Corporation Unknown device 056f (rev a1)
00:0e.0 IDE interface: nVidia Corporation Unknown device 07f0 (rev a2)
00:0f.0 Ethernet controller: nVidia Corporation MCP73 Ethernet (rev a2)
01:06.0 Ethernet controller: Atheros Communications Inc. AR5212/AR5213 Multiprotocol MAC/baseband processor (rev 01)
01:07.0 FireWire (IEEE 1394): Texas Instruments TSB43AB23 IEEE-1394a-2000 Controller (PHY/Link)
02:00.0 VGA compatible controller: nVidia Corporation GeForce 8400 GS (rev a1)

sudo lshw -C network
-network UNCLAIMED
description: Ethernet controller
product: AR5212/AR5213 Multiprotocol MAC/baseband processor
vendor: Atheros Communications Inc.
physical id: 6
bus info: pci@0000:01:06.0
version: 01
width: 32 bits
clock: 33MHz
capabilities: pm cap_list
configuration: latency=160 maxlatency=28 mingnt=10
*-network
description: Ethernet interface
product: MCP73 Ethernet
vendor: nVidia Corporation
physical id: f
bus info: pci@0000:00:0f.0
logical name: eth312
version: a2
serial: 00:1a:4d:5c:0f:2b
size: 100MB/s
capacity: 1GB/s
width: 32 bits
clock: 66MHz
capabilities: pm msi bus_master cap_list ethernet physical mii 10bt 10bt-fd 100bt 100bt-fd 1000bt-fd autonegotiation
configuration: autonegotiation=on broadcast=yes driver=forcedeth driverversion=0.61 duplex=full ip=192.168.1.103 latency=0 link=yes maxlatency=20 mingnt=1 module=forcedeth multicast=yes port=MII speed=100MB/s

In HW driver I've got:
Atheros HSL Tagged In use
Driver fi nDivia Tagged In use
Support for Atheros 802.111 WLAN Tagged In use

My poor Linux knowledge does not help me.
Anyone out there can?

Hey Onit72,
Have you tried using add/remove application to download one of the wireless Lan management tools such as KWiFiManager or SWScanner. I had the same problem on two computers but it was fixed by doing this.
Let me know how you go.

Check out the madwifi-hal package. It solved my Atheros related problems where the standard madwifi package didn't.

I tried first to install the madwifi-hal with the following procedure (found on the web) as it was the fastest try:
"gksudo su
cd /usr/src
apt-get update
apt-get -y install build-essential linux-headers-$(uname -r)
wget http://snapshots.madwifi.org/madwifi...0080903.tar.gz
tar xf madwifi-hal-0.10.5.6-r3861-20080903.tar.gz
cd madwifi-hal-0.10.5.6-r3861-20080903
make
make install
echo ath_pci | sudo tee -a /etc/modules
modprobe ath_pci
"
After a re-boot nothing changed.
If no other ideas I can try to replace Network Manager.