Can someone help me with getting my router to connect?

Beware, this is going to be kind of a long post because I want to be as clear as I can.

I just bought this Linksys routerlast week from Newegg because it was the best rated, and when I got it I quickly set it up and was pleased to find that it connected to my PSP fine, and I'm guessing it would have for my PS3 if I had tried it. I then ordered this Encore Electronics wireless USB adapter When I set it up, it got to a part where I had to enter in my DNS, subnet mask, blah blah blah in order to secure it. I think I entered it wrong. Because when I got off that, I tried to connect and it wouldn't work. So when I tried to get back to the part of the router setup where it asks for my DNS and everything, I was planning on erasing the details I gave so it would work again.

But I can't get to that part of the setup if I'm not connected to the Internet.... So I don't know what to do. Right now I connected to a neighbor's unprotected internet and it's working fine, so it's not the adapter's fault. When I connect the adapter to the neighbor's connection it's very weak and works well, but then when I connect it to my own router I can't get on the internet. What's going on?

Like the previous user stated, turn on DHCP by logging into your router. To do that open up a console window (Hold your Windows Logo Key & Press R and type in cmd and then press Enter). From here type in ipconfig and press enter. The gateway address listed is your router's IP address. Type that number behind http:// in your web browser, ie. http://192.168.8.1 ) and enter your username and password. Default is often admin for u/n and password for p/w (depends on router). Once in here you can setup your security settings (preferrably WPA2) and enable DHCP.