I've had my TiVo for four years. Up to now it's worked fine with the 
Telewest cable box but recently it's been having problems.

Often the channels don't change, either by using the TiVo remote or on a 
timed recording. Sometimes the attempted channel change causes the cable box 
to freeze, necessitating a reboot.

The problem is sometimes overcome by moving the second channel blaster a 
little in the area of the receptor on the cable box. However this only lasts 
a few hours before the problem reoccurs. (Note: I know you're only supposed 
to use one of the blasters and until recently I did, but now it seems to 
need both!).

I can then clear the problem by rebooting both the cable box and TiVo but 
this also doesn't last long. I've changed the batteries in both remotes too.

Is the problem caused by the channel blaster perhaps? I hope it's that, 
rather than the TiVo itself.

As my system is four years old perhaps there are better channel changing 
devices around now?

Thanks in advance :)