New network card in a Dell causes I.E. to stop working

I don't know if this is unique to a Dell XPS T500 but I have had this problem
on two different systems running 98SE. The system has an Ethernet card (Dell)
and connects to the internet through a Linksys DSL router and DSL modem. I am
adding a a wireless router and changing the Dell to a wireless connection. I
installed the new card with a 98SE driver and removed the Ethernet card. Here
is my problem:

- the system gets a DHCP address (WINIPCFG and IPCONFIG/ALL - says
everything is configured properly) but when I run Internet Explorer it fails
to find the internet connection (can't access anything on the internet).
- Cannot access the web interface on the router using the IP Address
- ping works to anything on the internet by address but not by host name.
- added DNS servers manually and can ping to host name but Explorer still
does not work, and still cannot access the router web interface.
- replaced my complete registry with a backup copy (that does not know about
the wireless card) and everything works fine.
- replaced the old ethernet card and removed the wireless card and the same
symptoms occure.
- replaced the registry again and everything works.

I have tried just replacing the Ethernet card with another one (DE450) and
the same thing happens. In all cases it is fixed with a restore of the
registry.

The other Dell does not have a registry backup - help.