Windows Live Messenger Internet Connection Problem

I am trying to get the Windows Live Messenger video chat to work, and it
will, but as soon as it started, the sound gets all choppy along with the
video. I found that Messenger says that I am connected to a non-UPnP
symmetric NAT, but I already set in the router to enable it and let it
through the router firewall. I also went into the Windows Firewall and set it
as an exception. I have tried everything, forwarding all the ports for video
chat and voice, but nothing seems to work. The sound is still messed up and
it still says my connection is non-UPnP. We had this problem with the same
computer before, but somehow I managed to fix it. The only problem is that
the hard drive crashed just a week ago, and I have no freaking clue how I
fixed it before. I know it was working because I was doing a video chat just
before the crash. Any help would be appriciated, thanks.



------------------------System
Information--------------------------------------------------
Intel Celeron 1.10ghz Processor
256mb RAM Memory
Dell Dimension 2100 Series
Windows XP Home Edition with SP3
Windows Live Messenger Version 14.0.8064.206
ZyXEL EQ-660R ADSL Router

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