Win7 must have something like Manage My Network Connections when R-clicking the Internet thing in the System Tray.

I've found a 'Network Centre' in the control panel, but can't see anything like that.

Microsoft gives this info:
If you enable ICS and then turn on network discovery in Network and Sharing Center, an Internet gateway device icon is added to the Network folder on the Start menu.

It shows the icon, and there's nothing like that in the start menu.

Don't think you searched hard enough. Look in the System Tray as I directed you.

The point I'm making is that this Internet Gateway could appear, not in Start Menu, even when you haven't enabled ICS, as you wouldn't if you were using a router, and that Internet Gateway could confuse a wireless device into trying to somehow think it's connecting to it instead of the router.

This happened to me with the Internet Gateway appearing on a non-ICS XP and confusing a wireless Vista. The symptoms were random discons of Vista, much like yours.

It's just an idea but worth checking.

I saw similar symptoms a little while ago with my smart TV unable to stream successfully or even connect on occasions.

Have you looked at how your router is utilising channels with the freebie inSSIDer?

In my case the shiny new router was detecting similar devices nearby and hopping channels to avoid Overlapping and Co-Channel interference. Other similar devices nearby did the same so my router would hop back with the result that client devices could see the network, then they couldn't, then they could. Throughput dropped alarmingly as the clients chased the router around the channel range.

Solution was to turn Auto-Channel off by selecting an empty part of the spectrum as possible. I did also lock the speed down to 144Mbps and hey presto normality was restored.

Thanks ..I've looked in the system tray, and it's definitely not there.

I haven't tried inSSIDer. I did see it in use some time ago, and to me, it looked quite complex ...but I'm not really clued up with wireless stuff at all.
I could try it tomorrow. I take it I need to have the notebook on and connected (or trying to) ?

Being on the last day to return the order to Amazon, I wasted no time in asking if I can still do so given the problems I'm having, and the fact that the earlier model worked perfectly.

You can only run inSSIDer on a PC with a wireless adapter, like your notebook. It does not need to connect to router; inSSIDer is seeking all wireless access points in vicinity.

Ah right! Thanks, I'll put it on the notebook and see if I can glean anything from it!

I think you will find the routers probably faulty. It could be the model that's generally problematic. Often a basic router for £30 - £50 will do the job very well without needing a reboot for numerous months. I'd personally return the billion router and look around, perhaps even same some money or if you're comfortable with the old billion go back to that.

I can advise you some routers I've used, a netgear I have has an uptime of over 3 months without any issues.

Well, I asked Amazon if they would let me return it even though I was a day over their 30day return policy, and this morning I have a 'yes', and an email telling me that DPD will collect it on 25th!
So, Amazon are being very helpful!

I've immediately ordered the 7800n.
Hopefully, by the time that wears out, they'll have likely resolved any issues with the DXL. It's been rock solid for wired connection though, just like the 7800n.

I had a Netgear which did work pretty well, but having a fairly long line, when it was replaced with the Billion, I got much better speeds and stability too.