Windows Operating system needed

That would be very helpful actually.  I actually went ahead and installed windows xp on it.  It works, but I can't get an internet connection because I don't have the drivers to connect to anything unless I had a modem that was hooked up to a phone line.  I might have to figure something else out.  I can't go to my nearest college because they check your card to make sure you're a student.  I'd go to my public library, only, I'd have to re-register with them since I haven't been there forever.  I might be able to hit up a friend about it too.  I'll see what I can cook up.  Heck as long as I could get the driver to use my wifi, then I could get the rest of the drivers at home.

Well, you can't usually "just" install the wifi driver ... you need to install the System Software and the chipset first, because those can change the way the wifi adapter behaves, and without them, there is a good chance the wifi driver won't install or won't work properly.

When you get an Internet connection, these are the downloads you need for minimal functionality to get your Windows 7 downloaded:

System Software:

ftp.dell.com/.../DSS_UTIL_WIN_R288017.EXE

Chipset:

ftp.dell.com/.../DRVR_WIN_R302424.EXE

The actual wireless driver you need depends on which device was actually configured in it:

Intel 5000-series:

ftp.dell.com/.../INTEL_MULTI-DEVICE_A08_R277771.exe

Dell 1397:

ftp.dell.com/.../R260736.exe

Or, assuming your router has an Ethernet port and you have problems connecting to your wireless network, you can install the drivers for the Ethernet/network port:

ftp.dell.com/.../NIC_DRVR_WIN_R213294.EXE

Ok so I downloaded the files on to a usb to upload to my laptop.  The first link didn't seem to do anything.  It had the popup box for extracting and installing, but when I clicked install, nothing seemed to happen.  The chipset link seemed to work.  The wireless links didn't seem to apply.    I was trying to figure out what type of wifi device I have installed.  I looked under Network Adapters in my Device Manager and it lists '1394 Net Adapter' and 'Broadcom NetXtreme 57xx Gigabit Controller'.  So both of the links for 1397 and 5000 may not apply.  The last link uploaded as well, but I had to go into the advance section to try to get a TCP/IP connection while using an ethernet cord.  I'm still using internet from a different source than the laptop as it still isn't working properly.  Perhaps there are some other drivers you can assist me with?

"The first link didn't seem to do anything."

It may not do much ... but the important thing is that it RUNS.  It should extract the contents to a C:\dell\drivers folder, then run automatically.

The ONLY wireless devices listed for the E5400 are:

Intel 5000 (5100/5300 use the same driver):

www.dell.com/.../latitude-e5400

Dell 1397/1510 (use same driver), so unless someone replaced the wireless module with another, one of the above should work:

www.dell.com/.../latitude-e5400

All links above should lead you to the same files I provided links for previously.

As for connecting via Ethernet ... depending on what device you are connecting to, you should not need to do any advanced setup/configuration, and if you do, you will need to know EXACTLY which settings to use.  What device (model of modem/router) are you connecting it to?

To determine for sure which wireless module you have, go to Device Manager (right-click My Computer, Manage), right-click on the device in question, Properties, Details tab, change dropdown to Hardware Ids, and give me the VEN and DEV ID's.

Well, there are a bunch more that you probably need ... IF you are going to use this long term.  Do you want to use XP long term, or do you just want to download Windows 7 to install that?  If you only want to download Windows 7 so you can install that, then you don't need to waste any more time with any other drivers.

I couldn't determine which type of wifi card I had by going to my device manager.  I popped the bottom of the laptop off to find I had a 5100 pro.  So I downloaded the driver for the 5100 wifi driver and it now works.  Thanks for that link.  Now I just have to figure out what other types of drivers I might need.

I would but I don't have a disk for windows 7.  And from looking around on the links that have been provided as well as doing other searches, if I was to obtain a disk or download it I would need to call into Dell or Microsoft and verify some  stuff, only problem is, I'm not listed as the registered owner even though I bought the laptop from a buddy I used to work with.  I've filled out the forms and all but  unless theres another way around it, I don't know what to do there...

"I would but I don't have a disk for windows 7."

I know, but isn't that what we are trying to accomplish - download a "retail" DVD ISO from which you can install Windows 7 (instead of trying to obtain actual Dell media)?

"And from looking around on the links that have been provided as well as doing other searches, if I was to obtain a disk or download it I would need to call into Dell or Microsoft and verify some  stuff, only problem is, I'm not listed as the registered owner even though I bought the laptop from a buddy I used to work with. "

You can download a Retail copy of the installation media from Microsoft's online partner, Digital River, from the links provided, then activate over the phone with Microsoft (not Dell) ... NO other verification is necessary!

Filling out the request form to transfer ownership, then request DELL installation media (which activates automatically and does not require activation), is another option, but is NOT necessary ... we are talking about two different options here.

Question (since I am confused as to what you want to do now):  Do you want to try to get a modern, functional operating system installed (Windows 7), or do you just want to run with the ancient, soon-to-be-end-of-life (no further security/stability patches/updates) operating system (Windows XP) that is on it now?