I have 2 computers running Windows XP SP2 networked via Ethernet cards and twisted cable, with ICS.connecting to the net by dial-up connection
I downloaded TCP Optimiser and ran it on the host computer , This wiped out the LAN connection. After I re-established the LAN I went on line, worked on the Host computer, connection speed was 115 kbps up from the usual 42.5 Kbps. However I had no INTERNET connection on the guest computer.
End result, had to restore saved settings on the host and do a system restore on the guest to restore to working condition.

Non existent help files in TCP Optimiser and scant FAQ's don't seem to help much, hoping someone here can set me on the right track.