I have an Ethernet switch and Windows XP Home. Previously the switch
was running fine, without a problem, and appearing in Network
Connections.

For some reason, the switch has disappeared from Network Connections -
all I can see there is my ISP dialup connection now. It's quite
confusing as I haven't installed any new software since this began
happening.

When I turn on my computer, the green light next to the plug I'm using
on the Ethernet switch lights up. However, as soon as the "Welcome"
screen appears on Windows, the light switches off.

Hopefully I've included enough information, will be happy to clarify
anything as required.