I had a computer today with a problem that every once in a while, the internet would stop working. There was no sign of the connection going out (wireless, wired, etc.). You would just be on a website and by the time you clicked the 3rd or 4th link, you’d see a “server cannot be found error”. To further test, I started a hefty download (Windows SP3) and sure enough, 30 seconds in, the download stopped and the error “connection reset by server” was shown.

Computer Info:
Windows XP SP2
Hard wired ethernet to router then to cable modem

I tried Winsock fixes, dnsflushing, network connection repair, etc. and nothing helped. I feel stupid just knowing that all it was was that this client had originally been an AT&T DSL customer and had the 2Wire modem/router diagnostics software installed. I removed it and the problem was solved! It looks like this software was running in the background trying to “fix” a connection that was no longer there.

Case closed.