raido no sound on 1997 Volvo S90

Hi I have a 1997 s90 the raido shows off on the display,but when I go to turn it on I get no sound or display.

Asked by for the 1997 Volvo S90
The radio has a 4 digit code that needs to be keyed in after the radio loses power, this is an anti theft feature. If you try unsuccessfully 3 times, the radio turns to "OFF". You will need to leave the radio turned on until it says "ON", then key in the correct code. You may need to go to the Volvo dealer to get the code, or check your owners manual.
1 more answer
The radio has to be in the on position for 2 hours non stop, then a 4 digit code will have to be enterd a card that came with the manual or get from the dealer. Each time the car looses power (disconnected from batter, it has to be reset).