Connections Reset Very High

I have a small office network with Windows Server 2003 and a DSL connection.
Everything has been fine for several months. Just this week I noticed a
drastic slow down.

When the Server is plugged into the network, my download speed is way slow.
It is in the 100-200 kbps range. It is normally 1.2mbps. I can unplug the
server from the switch and the speed goes back up to normal.

I opend up the performance monitor and added counters for TCP and noticed
that the Connections Reset counter is very high, in the 50-60 range.

Also, on Task Managers Network performance tab, the bytes sent counter is
way high. Are these normal?

If not, what could be causing this?
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Thanks
Dan Jurden