can't connect to internet using wireless from my Sony Vaio

Lately,my internet stopped working on my SONY Vaio VGN-NR120E.I checked the other computer and they were working perfectly fine with the wireless network. My sony laptop was catching the wireless networks but it wasn't connecting to one.Desperately,I thought it should reinstall the windows Vista.I didn't recieve a windows vista cd with this computer from sony so I installed the windows vista that I had from my Dell laptop.But the problem persisted.Later,my internet provider told me that I need to install netwrok adopters as thats the only thing that seem not to work and thats the message I get when I try to connect it wirelessly.I did from Sony website and still nothing.I am someone who knows very little about computer and softwares.Is there anyone who can help.and Yes my computer doesn't renew the IP address after this problem.For now,my cable guy has connected my computer directly to my modem using a USB cable so I have to use it as a PC and not as laptop.any ideas what I can do to make it work wireless once again.

try going to manage network connections and make sure your wireless card is active. If it is and not working try to uninstall and reinstall. All the software should be on your software back up on the "d" drive system backup. Then if that doesn't do the job try a USB external card from a friend as your built in might be bad. Some Sonys have a switch on the front of your lop top try that first.