There aren't many clues to go on. All of the dash lights coming on means the alternator stopped generating and the engine is not running. A battery with less than 10V will not get the starter motor turning, usually a 'click' is all. Less than 9V at the battery and nothing will happen.

My suggestion is to check the wires at the alternator and verify that none of them came loose. Then check the wire from the battery to the starter, ditto. And check the battery voltage.

The key switch might also be at fault. This can easily be checked by measuring the draw at the battery when moving the key to posIII.

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My back feels better when I sit in a Volvo seat