I am pretty much clueless about operating systems and such, so I tried a couple of versions of Linux: Knoppix and Slax from live CD's. In both cases I could not get on to the internet because they would not recognize my wireless connection, and I'm not confident enough to go mucking around in the system.

How do I get my wireless to work?

Another thing is that I can't locate any of the existing files on my computer after I load Linux.

I know. I'm hopeless.

It would help to know what kind of hardware you have, laptop or non-laptop, wireless card, CPU, and RAM.

If you've got a P IV (Pentium IV) CPU and 512 MB RAM, you should be able to use Ubuntu or XUbuntu, whose wireless is in most cases self-configuring. It's a little more complicated if you are WEP-encrypted.

Depending on your distribution, your network config files are almost always under /etc, mine are under /etc/network (Ubuntu). On Red Hat the configuration files are under /etc/sysconfig/networking.

Compaq Presario C500 laptop with integrated wireless and intel Celeron M. Not sure about the WEP encryption.

Ubuntu 7.10 should be able to pick up your wireless card and set it up once you provide the encryption password. I have a presario and an inspiron that are both older than your C500 that work with ubuntu 7.10.

cmnorton,
Could you point me in the direction of a guide to using WEP in Ubuntu (7.10)? I've got my wireless card up and running and my router showing up in Network Manager, but every time I enter the key (64 bit hex) it comes back asking for a 128-bit passphrase. Thanks.

I am not sure which distro you are using. I am only familiar with Network Manager on Ubuntu.

Network Manager detects your wireless network is web-encrypted, and prompts you for a information. It is at that point you have to tell Network Manager what you are supplying. I have used my original ascii passphrase and Network Manager has wep-encrypted it, and it was accepted by my Linksys wireless router.

If your network is expecting a passphrase, my guess is you are being prompted for whatever generated the hex key, the ascii text.

I am using the i86 desktop release of Gutsy.

The hex key is actually printed on a plate that is screwed to my router. (I'm not sure if that's relevant, but I try to be thorough where I can.)

How might I be able to derive the ascii text that generated the key from the hex key that I already have?

You may try editing the ifcfg-ethN file directly. (look in /etc/sysconfig/networking/ for an ifcfg-* file where the rest of the name matches your device)
Are you certain that the router doesn't use wpa-psk. Using WPA instead of WEP would be advisable since WEP is thoroughly broken. A war driver will be able to crack it in 1-2 minutes. Maybe faster than it would take you to authenticate using a known key!

The router may have a web interface where you can change the encryption used and update the key with a new one. They should be changed occasionally anyway.

The text passphrase probably goes thought some complicated hoops to derive a 32 byte hash value. It is probably a one way hash, which means that you can't go backwards.