Is this a new install on the laptop or has it been working OK all
along? Have you done some up dates or installed some software that
could of affected it?

So when you first turn it on it gets the address from the router OK.
Are you using DHCP or a dedicated address? I presume you mean the
browser quits working.

Does Email still work OK to your pop server after the trouble starts?

Are the lights on the router showing correctly for a working circuit
to the laptop the same as the desktop before and after the trouble
starts? Are there any differences after the trouble starts.

Do the router leds flash on the router port to the laptop after the
trouble starts? In ten to twenty minutes when Gaim quits?

Does restarting the browser do anything for you?

Can you ping the router?

Can you ping any other machine on your network?

Can you ping your own loopback?

Can you ping anything?

Can your desktop ping the laptop or access the laptop?