They deactivate. But it’s a distinction without value for casual conversation.
If you write an executable to a file, does the program still exist? Or is its existence as a program depend on it being loaded in memory and being executed?
They can deteriorate to the point that they can no longer reproduce, so, close enough?
You are right. 'die' refers to falling apart.
I am not an expert but I believe the reproduction of a virus is more 'chemical' than 'biological'.
It's very much biological. Viruses, like our cells, consist for a large part of protein, which degenerates when above 65 degrees for some time.