Wireless Network frustration and WZC

I read the wireless network sticky, but I must ashamedly admit I'm still confused.

The main pc in our home has XP SP2 and has a hardwire connection to the internet through our router, which is an Asus WL500G.

The second pc has XP SP1 (I guess - it's not 2 and I can't upgrade it) and is supposed to have a wireless connection, but is highly unreliable for reasons incomprehensible to me. It seems to work best when our nearest neighbor is not online, but I don't know. The most common error is the 'limited connectivity' one.

Now I would also like to securely connect two Dell 1501s to this setup. Both are on XP SP2. They connect flawlessly to the internet from anywhere in the apartment, but:
Our internet connection turns out not to be protected. Initially, someone else setup our network and I thought he had everything squared away properly. I went to look today and well, guess not.

I tried configuring the internet connection settings from my notebook, but was afraid to have locked myself out of internet after the Dell nor the Windows internet utility wouldn't connect me to the network properly. (Obviously, it did eventually but it scared me a little and so I changed everything back to the original settings because I knew they worked. )

The second problem is that the WZC on at least 1 Dell (not sure about the other) won't start automatically, even though it says it should, and will also just stop without notice. This could be a potential problem for me when I go back to college next week and need to use the internet there. The university website specifically states that the WZC-thing needs to be turned on.

So, in short, two questions:
- How should I go about setting up this network?
- How do I get WZC to do as it's told?

Thanks guys.

 

Nobody?