Get initial internet connection then lose ut!

Hello,

I have a Netgear MBR624GU wireless router. Attached to the router is a Vodafone dongle (I'm in the UK).

I use this router to simultaineously connect two machines to the web. One is a Dell laptop, the other a Toshiba notebook. Both run on XP Pro SP3.

My problem? The Dell - no problem. The Toshiba - well, this only started a few weeks ago. When I open either Firefox or IE I get to my home page (google.co.uk), I can get the result of a search but can navigate no further - page cannot be displayed etc.

Turning off the notebook (I don't always trust a reboot) and turning on again makes no difference - nor does rebooting the router. Only a prolonged period of the router being off seems to make a difference.

At this time, I have connected to the routers web interface from the Dell (indeed, I'm using the Dell to make this post) in another tab, gone to the 'Attached Devices' and not even this machine is displayed!

Any thoughts/advice most welcome,

Tim