what are the impacts on software failures?

Answer 1

The impacts can ranges from loss of information, money, properties, to loss of lives.

One sample is the Y2K bugs.

Another sample is The Gulf War.
The program of 'Patriot Missiles' were written in real-time language ADA. Somehow, it FAILed to intercept scud missiles, and so brought loss of properties, money, and lives (see Failure at Dharan).