FYI: There's a kernel sockets leak in the 64-bit edition of that OS in
combination with multiple CPU cores (meaning on any slightly modern CPU).
You might be running into that now or later. See:
http://support.microsoft.com/?id=2577795
The issue is over a year old and there's still no Windows update that fixes
it, except for the hotfix in linked article. Apparently the fix will be in
SP2, but there's no ETA for that.