You sure you can't get another modem to try?
Ask for a Surfboard to try just for a laugh, they can only say no! Even after a lightning strike that took out the USB port on my SB4100 forcing a switch to Ethernet, mines been running great! It's been switched on for best part of 4 years now and is not even luke warm
I'm surprised those silver NTL modems still work after a few hours of being switched on, they get flippin hot!