Hi Matt and welcome.
First port of call is the battery. If the battery is more than 5 years old I would change it. These cars, like all modern premium cars, eat up the amps at an alarming rate so unless your battery is recharged often by a long run it will suffer a drop in voltage sufficent to upset at least one of the many computer modules. If possible put it on charge and see if that solves the problem. Personally I would use a Ctek charger at least weekly. Make sure you use a charger capable of handling the AGM battery. Also if the battery is low the S/S will not be working.
Also worth checking for water in drivers footwell as the washer bottles can leak and flood the electrics causing all sorts of wierd problems so fingers crossed yours is nice and dry...
Good luck,
John