The "but it doesn't stop people dying" contingent are being deliberately and defensively obtuse on this thread. Of course money doesn't stop people dying of incurable diseases or in unforseen accidents (though there is a correlation between both absolute and relative poverty and ill health and reduced life expectancy at a population level within rich westernised countries as well as globally).
Essentially as Whosorrynow says money (not incredible wealth but enough money not to have to worry about how to buy a new washing machine or pay for car repairs, pay normal household bills and put good quality food on the table, pay for extra services where necessary, whether extra carers for an elderly parent, a cleaner, childcare/ babysitting, a taxi when the train is late or its raining or you're just tired, a meal out or take away when you are just to tired or late home to face cooking, a bought sandwich instead of going hungry when you're in hospital with a sick child etc etc)
is a necessary but not sufficient condition for happiness.
Money, as people keep saying, doesn't guarantee happiness but the lack of it can make happiness impossible.
Not riches, but enough money.
People who keep pointing out that there are rich unhappy people are largely missing the point that not one single poster is claiming money can guarantee happiness or prevent tragedy, but are saying that the lack of money can make a bad situation impossible or an otherwise good situation bad.