I have checked all the fuses but everything appears to be fine.

 

Try to jiggle the ignition key to see if that helps. Older Volvo's have problems with the ignition.

 

same problem. No reading lights when I push the buttons BUT do come on when I open the doors. Sunroof stuck in up position as well.

 

The problem comes from either you replaced your power mirror recently or the alarm siren battery has failed. I had to replace the siren that is located under the front fender well of the passenger side. Wheel off and fender plastic wheel well off(drill rivets out) you will then see the alarm siren.
Also to test the mirror possibly being the cause i would suggest unplug the mirror and reconnect. The siren will sound for about 30sec and stop. the sunroof will work for a short time after (I give it 5 min), the reading lights will also work albeit temperary. Hope this helps you out.