Limited or no connectivity...

Hi,
I'm having a lot of trouble with my wireless connection on my new laptop
(I'm a Mac person!)
Until about a week ago, I only used my laptop to connect to the internet at
home. My home wireless network is unsecured, and I didn't have to do anything
special to configure the wireless settings (it just worked when I clicked
"connect".)
However, about a week ago both my PC desktop computer at home and my PC
laptop stopped picking up the internet. Both reported strong signals, but no
internet connection could be accessed. My roommate was able to fix the
desktop computer, but my laptop remains unfixed.
In "Network Connections", I disabled my Local Area Connection, hoping that
might work, after following the instructions on:
http://www.ezlan.net/wireless.htm
After doing this, I began to receive the message:
"Limited or no connectivity", and after clicking "repair":
"Windows could not finish repairing the problem because the following action
cannot be completed: Renewing your IP address. For assistance, contact the
person who manages your network."
I am pretty much stumped. Any ideas?
Natalie

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