Volvo Repair: Ignition/Starting, degree temperatures, volvo s60

Question
I have a 2003 Volvo S60 which will not start after the engine gets hot.  My mechanic kept the car for 8 days and said it started fine every time, but the day I brought it home it refused to start after driving it 20 miles in 90 degree temperatures.  The battery is good.  The car just does nothing when the key is turned.

Answer
Don, did the car have any kind of codes stored?  We have seen the antenna rings go bad but shouldnt have anything to do with the temperatures.  Im thinking its that or another module misfunction.  Hard to say without doing tests since everything is computer controlled on these things.  Roger