Just got Debian loaded up on an older Thinkpad T400 model 2767WHU. Currently connected to the internet via Ethernet but am unable to get wireless working though I've followed many guides and have been googling for hours.

Would anyone have the time to walk me through this? I can't even figure out what wireless card I have.

The network icon in the top left says wireless hardware disabled.

Thanks!

Post output of

Network controller: Intel Corporation Ultimate N WiFi Link 5300

I think the package you need is firmware-iwlwifi

Try this https://wiki.debian.org/iwlwifi

I've already installed the package but do not know how to continue from that point.

# modprobe -r iwlwifi ; modprobe iwlwifi

See the link provided above by Eddy.

Can you provide the output of /sbin/lspci?

Entered that line and rebooted. Wireless still says unavailable. D:

Output of iwconfig?

Hopefully I did this right?

00:00.0 Host bridge: Intel Corporation Mobile 4 Series Chipset Memory Controller Hub (rev 07)
00:01.0 PCI bridge: Intel Corporation Mobile 4 Series Chipset PCI Express Graphics Port (rev 07)
00:02.0 VGA compatible controller: Intel Corporation Mobile 4 Series Chipset Integrated Graphics Controller (rev 07)
00:03.0 Communication controller: Intel Corporation Mobile 4 Series Chipset MEI Controller (rev 07)
00:03.2 IDE interface: Intel Corporation Mobile 4 Series Chipset PT IDER Controller (rev 07)
00:03.3 Serial controller: Intel Corporation Mobile 4 Series Chipset AMT SOL Redirection (rev 07)
00:19.0 Ethernet controller: Intel Corporation 82567LM Gigabit Network Connection (rev 03)
00:1a.0 USB controller: Intel Corporation 82801I (ICH9 Family) USB UHCI Controller #4 (rev 03)
00:1a.1 USB controller: Intel Corporation 82801I (ICH9 Family) USB UHCI Controller #5 (rev 03)
00:1a.2 USB controller: Intel Corporation 82801I (ICH9 Family) USB UHCI Controller #6 (rev 03)
00:1a.7 USB controller: Intel Corporation 82801I (ICH9 Family) USB2 EHCI Controller #2 (rev 03)
00:1b.0 Audio device: Intel Corporation 82801I (ICH9 Family) HD Audio Controller (rev 03)
00:1c.0 PCI bridge: Intel Corporation 82801I (ICH9 Family) PCI Express Port 1 (rev 03)
00:1c.1 PCI bridge: Intel Corporation 82801I (ICH9 Family) PCI Express Port 2 (rev 03)
00:1c.3 PCI bridge: Intel Corporation 82801I (ICH9 Family) PCI Express Port 4 (rev 03)
00:1c.4 PCI bridge: Intel Corporation 82801I (ICH9 Family) PCI Express Port 5 (rev 03)
00:1d.0 USB controller: Intel Corporation 82801I (ICH9 Family) USB UHCI Controller #1 (rev 03)
00:1d.1 USB controller: Intel Corporation 82801I (ICH9 Family) USB UHCI Controller #2 (rev 03)
00:1d.2 USB controller: Intel Corporation 82801I (ICH9 Family) USB UHCI Controller #3 (rev 03)
00:1d.7 USB controller: Intel Corporation 82801I (ICH9 Family) USB2 EHCI Controller #1 (rev 03)
00:1e.0 PCI bridge: Intel Corporation 82801 Mobile PCI Bridge (rev 93)
00:1f.0 ISA bridge: Intel Corporation ICH9M-E LPC Interface Controller (rev 03)
00:1f.2 SATA controller: Intel Corporation 82801IBM/IEM (ICH9M/ICH9M-E) 4 port SATA Controller [AHCI mode] (rev 03)
00:1f.3 SMBus: Intel Corporation 82801I (ICH9 Family) SMBus Controller (rev 03)
01:00.0 VGA compatible controller: Advanced Micro Devices [AMD] nee ATI RV620 [Mobility Radeon HD 3400 Series]
03:00.0 Network controller: Intel Corporation Ultimate N WiFi Link 5300
15:00.0 CardBus bridge: Ricoh Co Ltd RL5c476 II (rev ba)
15:00.1 FireWire (IEEE 1394): Ricoh Co Ltd R5C832 IEEE 1394 Controller (rev 04)

Says that iwconfig command is not found?

Type it as root (su -)

lo no wireless extensions.

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

eth0 no wireless extensions.

(added spaces to avoid emoticons)

Looks like your wifi device is recognised as wlan0. Do you run any network manager (For example: NetworkManager or wicd)?