Terrible pixelated picture/Jumping Starview Box

My Starview box seems to have gottten ill. I have put in correct codes done factory resets etc but i still get jumping pictures and sound some channels are worse than others .
We have resorted to watching Freeview as its just so annoying.
Can anyone give me any clues as to what may be wrong

 

Have you checked your cabling and if you have a weal signal try a booster.

 

Cabelling is fine. Where would i get a booster from?

 

ud pick one up in most shops that sell tvs,argos,malpins(ETC)