Strange wireless problem in Ubuntu

Hello all,
Alright I have a problem that has really puzzled me. I currently have installed kubuntu edgy on my Dell inspiron 1150 and followed the instructions here,

http://www.ubuntuforums.org/showthread.php?t=185174

in order to set up my wireless card. It worked great for two days! Now though, I can't find any wireless networks around my apartment when before it found four. I know that my network is working because I dual-boot with winxp and it found my network easily. I'm kinda new to linux and especially kubuntu, but does anyone have a clue as to what went wrong?

As an edit, I have am able to connect to wireless networks away from my apartment I have just noticed. So this is not an overall problem, but can anyone think of why I can see networks away from my apartment but not in it. Windows can see them there, so I know they exist.

what if you run

Code:

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sudo iwlist wireless_device_name scan

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If you don't know the name of you device run sudo ifconfig

I ran the command and I can see my network as well as the other networks around my apartment. So I can detect them, but how can I connect to them?

what program were you using to connect before? The dirty way is to run

Code:

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sudo iwconfig wireless_interface your_essid

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I tried the command that you gave me and I got this response (my network's essid is NASA):

Code:

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stephen@stephen-laptop:~$ sudo iwconfig eth1 NASA
Password:
Error : unrecognised wireless request "NASA"

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Did I type the command incorrectly? Also, I'm currently using KWiFiManager to connect to wireless networks.