WARNING: This page is about a different car, the 2002 Volvo C70, 2001 Volvo C70, 2000 Volvo C70, 1999 Volvo C70, and 1998 Volvo C70. However, it is still accessible from the selected car via links, so may be relevant.
Fig 1: Identifying Catches And Front Panel Of Audio Unit
Courtesy of VOLVO CARS OF NORTH AMERICA.
Remove:
the front panel
the audio unit. Fold out the 4 catches on the sides. Press in the retaining clip on the top side and press out.