cannot recognize base so set up fails on laptop

I have a MS Broadband Router MN-700. (All hard wired) I
have connected our two desktops to it without any
problem. When I try to set up the laptop it fails to find
the base unit.
Today I discovered that my laptop PCI adapter (built in)
works fine until I try to set up the router. As soon as
the adapter settings are changed the adapter lights stop
working. I am using a floppy to set up the settings.
I have tried changing the settings manually and automatic.
When it is automatic the subnet is 255.255.0.0 but the
router subnet is 255.255.255.0.
I have tried uninstalling the network card and
reinstalling it. I have removed the software from the
laptop and then reinstalling it.
The laptop is a Toshiba Satellite 1800 with an Intel
8255x-based ethernet adapter (10/100)
Thanks for your help.

Laptop computer is XP Home (XP Pro is on desktop)

MAC is not checked

ethernet cable works fine

I use dsl for internet connection