welcome to the world of digital TV...god help us.
The picture breaking up is caused by impulse noise, and digital signals suffer badly from them. The impact can be reduced but at a cost.
1. replace the aerial with a wideband one with a built in BALUN, often sold as digital aerials.
2. replace all downleads etc with decent double screened coax.
this can be a diy job but a pro with the right test equipment will be able to align the aerial properly.
with regards the thing downloading new software overnight, not a lot can be done, its a sad fact of digital..........................