wireless can ping but can't browse internet w/ ie

Sorry to raise a similiar issue. I found a lot of problem related, but
I still didn't solve my problem.

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My home network consists of one xppro, one win98se and a d-link di-514
wireless router.

the xp box connects to router in wire. Everything works fine.

the win98 connects to router in wireless pci card (tp-link wn250,
based in realtek 8018L chipset). The win98se is a very clean system. I
just install the system from an empty harddisk and no other
software/hardware.

In router, I set win98 box as static dhcp client. In win98, I
explicitly set its DNS server as 192.168.0.1.

For diagnose, I turn off WEP in router and win98. The signal strength
is ok. I ping 192.168.0.1 with 200 packets, 22% are lost.

From win98, I can ping the router (192.168.0.1) and internet IP, e.g.
64.233.161.104. sometimes I can ping internet name, e.g.
www.yahoo.com, sometimes I get "unknow host" reply.

But I can never browse any page, esp. I can't browse
http://192.168.0.1 which is the router administration.

What's the problem here? Do you think this is a hardware issue or
software one?

BTW, previously I install a wired pci network adaptor in win98 box and
it also works well for ie browse.

Your response is highly appeciated.

David