2 NIC for LAN and Diaup networking for Win98

I have win98 with PII and 2 NICs (NIC1 distinct ip for
ISP1 thr network nbd ;the NIC2nd for local workgroup
different ip ).The ISP is thr a DNS and a gateway.I have a
modem link through dial up thr another ISP2 ) I find that
since the ISP1 services are started I am not able to logon
to ISP2 after disabling NIC1 and NIC2 and only keeping the
Dialup adapter connection.The password is not accepted
which was working and not been changed.Advice the Procedure