Wireless on my Dell Latitude E6400 switched off and I can not turn it back on. Any idea?

you need to download your wirles driver from dell official website

iwill provid a link for your help http://www.dell.com/support/drivers/us/en/19/ProductSelector/Select

The Dell Latitude E6400 laptop comes with an Intel Core 2 Duo processor for fast computing and an NVIDIA graphics card for video playback, gaming and Web browsing. The laptop has a built in Wi-Fi card, letting you connect to the Internet on-the-go. However, if you're unfamiliar with Dell or the laptop's factory installed Windows Vista operating system, you might not know how to enable to Wi-Fi.

Slide the switch on the side of the laptop toward the front of the laptop. This switch enables Wi-Fi connectivity on the Dell Latitude E6400. When switched into the back position, the Wi-Fi is turned off. Turn on your Dell Latitude E6400 laptop and log into Windows Vista. Click on the Windows "Start" button. Click on "Wireless," located in the Start menu's "Show" list. A list of currently broadcasting wireless networks appears on screen. With your Wi-Fi enabled, you can connect to any of these available networks. Secured networks ask you for a password when you click "Connect," while unsecured networks connect automatically.

Plug in the usb, make sure the batteries are fresh, Windows should find the driver automaticly when you plug in the USB, if not reboot the computer with the USB in the laptop, if the mouse has a on/off switch make sure it's on. If the mouse came from a All-in-One PC like a HP Touchsmart or similar PC it will not work.

On either the right-hand (I believe) or left-hand side, there should be a switch. Flip it to the "on" position to turn the wifi/bluetooth radio on.

Hit F12 at the Dell logo screen when you first turn on the computer. Run the diagnostic to test the hard drive. I'm 99% sure the dirve is bad.

#1 ensure the wireless switch on the right side of the chassis is in the forward (On) position (I accidentally turn my wireless off about once a month putting the system in my carry bag.)
#2 if no change reset BIOS defaults
#3 Fn + F2

Hi,

You can use the ethernet port or the wireless LAN of your laptop to connect to the internet. You can refer to the link below for the specification of your laptop

http://gdgt.com/dell/latitude/e6400/specs/

Also refer to the link below for the location of the Ethernet LAN port of your laptop.

http://gadgets.softpedia.com/images/news/Dell-Latitude-E6400-Notebook-Review-66.jpg

hi

go to this link, review
What You Need to Establish a WLAN Connection http://support.dell.com/support/edocs/systems/ins6400/en/om/network.htm#wp1052373

1. Click the Start button, point to Settings, and then click Control Panel.
   
   
2. Double-click Network Connections.
   
   
3. Right-click the Wireless Network Connection icon, and then click View Available Wireless Networks.
   
   

If the Choose a wireless network window states Windows cannot configure this connection, the wireless network card's configuration utility is managing the wireless network card.
If the Choose a wireless network window states Click an item in the list below to connect to a wireless network in range or to get more information, the Windows XP operating system is managing the wireless network card.

One of the "F" keys on your laptop has a wireless tower icon on it (looks like a straight verital line with commas on either side). Press that key without holding down the "fn" key and your wireless should activate.

make sure the wireless switch is on then try to update the wireless driver of your computer. you can download the latest wireless driver from your computer manufacturer's web site then restart the computer