I have a similar problem which started at the end of last week.
If I try and visit the site
www.gfxartist.com the modem stops responding and after a few seconds the modem reboots.
One or two other sites cause the same problem, but the vast majority of sites I've visited work fine.
The odd part is that if I disconnect the modem from the router and connect it directly to the main PC the problem goes away.
I tried a different router and still had the same trouble.
Any ideas before I call NTL ?
downstream signal to noise 32db
power 1dBmV
upstream power 34dBmV
Using an SB4100
Thanks,
Dan