Er.. it's fixed! For me, at least. Although I have no idea why. I don't know if NTL did something, or if slapping the modem and router about a bit did it. I doubt what I did below did something, but I thought I'd mention it anyway..
I unplugged the CM from the router and turned it (CM) off for a minute while I got the USB drivers ready for installation. I also turned the router off. I plugged the CM back into the PC again but via a USB cable this time. Installed the drivers, and restarted as the connection seemed dead. PC rebooted, but connection was still dead. I decided to leave IE to do its crappy
Detecting Proxy thing which never seems to work and bugger off for about ten minutes.
I came back and finally I had internet access again. I jumped onto a Ventrillo voice chat server and stayed for a while. No disconnections! My IP address had changed, but not by much: very last digit went up by 2. Uh.
Then I ripped out the yucky USB connection, turned CM off, plugged the CM into the PC directly, turned CM on again, and made Windows hand out a dynamic IP (I normally use static IPs on the LAN). Connected again to Ventrilo and it didn't disconnect at all. Things are looking good.. except for the router. I need to buy a wireless router anyway, so it wasn't so bad after all.
I then added the router back into the setup and it's been working fine ever since!
It can't be a lose connection because either the connection would be On or it would be Off. Anyway, Windows didn't complain about an unplugged network cable. The router could've been b0rked somehow and the power down fixed it. Hell, even turning the CM off for a while may have sorted it out. I had a Motorola SurfBoard 4100 at my old place, and so don't really have any experience with the Ambit.
But one thing: how come other people are getting the same problem? I can only really put it down to NTL having done something about it.
Hey Nostra - thanks for your help on the phone! Did that other person that called you have the
exact same problem as me? If so, then thanks to you and whoever else sorted the problem out.. for me, anyway.