Vista - Connected with Limited Access

I recently connected my computer running Vista to a new network. My internet
connection was working fine for about two weeks and then started
disconnecting me. I keep getting the "connected with limited access" message.
It will connect for 10 minutes tops and then drop. The signal strength is
excellent, so that isn't the problem. I downloaded the hotfix on the windows
site, but it told me that I didn't have the problem the hotfix was supposed
to address. Does anyone know what my problem is and how to fix it?