Ad Hoc Problem: ping works, nothing else does!

I've just killed a day trying to get this to work, so any help would be
appreciated!

I'm trying to connect two computers (desktop and laptop) via wireless ad
hoc. I can ping both IPs without problem, but cannot browse the network, use
shared internet (though the laptop see that it has been shared), or use
shares. I have tried it with and without firewalls and WEP. Nothing seems to
make any difference. Sometimes (rarely) I can browse and see shares, but just
as quickly they fail again.

The desktop is connected using Netgear's WG121 Wireless USB 2.0 adapter.
Desktop settings:
IP: 192.168.0.1
Subnet: 255.255.255.0

Laptop settings:
IP 192.168.0.2
Subnet: 255.255.255.0
Gateway 192.168.0.1

For both computers:
LMHOSTS is disabled
NetBIOS is enabled

I've tried every possible combination I could think of and scoured the
Internet for HOURS!

Oh yes, I had both computers on a wired, hubless network just before I tried
switching and everything seemed to be working fine.

Hoping someone out there has the "magic" answer...