I have a similar problem with my BV7-32. It all started when plugging in the Wii that Father Christmas brought for the children. As soon as I attempted to set the AV2 input on my Beo4 options the TV froze, the menus gave up working and then after 15 secs the whole set would simply switch off, leaving a strobing standby light.
As a quick fix, I found switching my 7-32 from DTV to radio via my Topfiled PVR remote enabled me to unfreeze the 7-32 but the Beo4 only now works in terms of turning the 7-32 on and off and volume: I have to use the Topfield PVR remote to change channels, etc. I'm also seeing a more narrow screen on BBC channels (cannot access menus to rectify the problem).
Somebody from my local B&O retailer came out a few days a go and left me with a frozen 7-32 again, which I had to correct myself. It would appear B&O haven't picked up on this problem yet. He was going to check the internal B&O technical sites to see if this problem had been flagged yet.
I wonder if you have third party technology working with your 7-32 also? This might help us to identify the cause.
That said, we too have had heavy snow up here in the UK for the first time in a long time - so I'm wondering whether your temperature theory might have some truth about it. Our house is very old and the 7-32 sits next to an inglenook fire place through which the cold wind has been blowing all Christmas when we're safely tucked up in bed at night.
Any theories/suggested solutions most welcome!
Best
Ant H