There is some confusion here. You can't get Freeview through a cable box. They are two different services one (Freeview) comes from an aerial and a Cable Service (e.g. Virgin Media) via a cable from the street.
Try a NEW question with what you have: Freeview or Cable. BTW. If it is Freeview this question has been answered many times before and so I suggest a search here.
T
August 2009
Low signal through cable tv, is usually poor connections, low quality cable or electrical noise, make sure the cable connections are tight, they screw together, use a high quality cable, and make sure the cable is away from any other electrical cable as best as you can. Also make sure the cable is as straight as it can be, i.e. dont coil it up as this produces its own aerial effect pulling it away from the tv/box
Will
August 2009
Automatic Answer
While you wait for answers, we may have found some information which could help you.
howtomendit.com for free repair help, information and advice.
Try fixfault.com to fix satellite receivers.