Ferguson F2620LVD Problems!!!!!!!!!!!?

I have one of these and have had it for just under a year, but recently it has decided that whiule i am sat watching something it is just going to turn itself over through the freeview channels.
i thought it could be something to do with the digital switchover but if anyone ahs any ideas of how to stop it doing that i would be very grateful, oh n the signal strangth is abnormally low at 60%
thankyou Xx