Volvo Repair: Volvo S70 Service light, service reminder, volvo s70

Question
Hi my 1999 volvo S70's service light comes on eveytime i trun on the car stays
on for a little bit then goes off after a couple of minutes.  Why does it come on?  
I had my oil changed recently, but it wasn't done by a volvo dealer....does
something need to be reset.......what do you think wrong....

Thank You Ryan

Answer
Ryan, its prgrammed to come on every 5k miles as a service reminder.  The dealer forgot to reset it.  Reset it  by doing the following.  Turn key on pos 1 while holding the odometer reset button.  Keep holding it in and turn key to pos 2.  Wait for service light to flash.  Its now reset.  Roger