Question about socket error/limited connection issue

Archived from groups: microsoft.public.win2000.networking,microsoft.public.win2000.setup (More info?)

I upgraded my "most used" internet machine to Win2k, about a month
ago. At the same time, I upgraded it to a new mb and processor
(2.8Ghz), with 1Gb of memory. The upgrade to Win2k was done
via a fresh Win2kPro install, to this new, never before touched,
processor, memory and HD.
My internet connectivity is now terrible. When I open 3 NNTP
connections, all subsequent email client and subsequent web browsers,
etc., all FAIL!! (Message is "socket error, unable to resolve host.)

Before this upgrade, I ran Win99SE on this machine w/ a 700Mhz
processor and 512Mb of memory. I was able to have 1telnet session,
1Thunderbird Email Client, 6 NNTP connections, 2 or 3 Netscape
Browser instances and 1 ftp session ALL active simultaneously. I
could have more depending on other uses of
memory.

I'm using the same email client, telnet client, web browser and
new binary news reader. Although the news reader seems to
have a performance issue, I'm certain it is not responsible for
all of the socket error/limited connection problem.
With another newsreader, I can get one more connection
open, but still nothing like I could before. When I don't use
a newsreader at all (just mail and browser), I can open a
zillion browser sessions (at least 12) + 1 mail and 1 ftp.

I've tried this scenario with multiple news readers and multiple
news servers (usenetserver and giganews).

Does anyone have any idea what is causing my problem and how I
can correct it???