1997 Volvo 960 Radio Code

Computer problem
1997 Volvo 960 6 cyl Wheel Drive Type unknown Automatic 110, 00 miles

My battery went dead and had to be recharged. Now the radio needs to be reset with a code. I was never given a code. How do I find what the code is? I'm the second owner of this vehicle. It was purchased as a gift from my husband, who I am no longer with. He said he dosen't have it either. Can you help me?