A dead battery does not produce any error messages, regardless of the length of time it has been dead.
IF you were to "jump" start the car with voltage that is too high, that could fry some of the computer components. Or, there just might have been a pending problem with the seat belt that just happened to rear its ugly head when the above person installed a new battery.
A warning light, as much as I hate them, needs to be diagnosed to determine the actual fault. If the SRS light is on, the seatbelt pretensioner or airbags may not deploy when you need them. For those that drive around with the SRS light on, I suggest they keep the seat belts tight for all occupants and drive around pretending that they are targets of pick up trucks and SUVs.

There is an outfit in Europe that makes a Volvo scan tool that can display and erase all Volvo codes from 2001-2007. It does cost a lot, about $300, but 3 trips to the dealer and you should be ahead of the game.

Klaus
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Common sense trumps a PhD