First, check the fuses. Next pull the battery lead, wait 5 minutes and reconnect it. That solves most of my Volvo's electrical gremlins but you have to set you clock an radio presets again.
Your next option is to check the forums. Here is one I use frequently:
http://www.volvoforums.com Hopefully this will work because your next stop is a Volvo service center which is never fun or cheap.
If this helps please vote for my solution.
FYI: Consider this when it comes time to replace it: Ford bought Volvo for $6 billion in 1999. They added a huge amount of technology to the vehicles which caused so many problems that they sold Volvo to a Chinese company for $1.6 billion in 2010. The Volvo name has been in a rapid decline and it looks like it just bottomed out. It's a shame because I still think they make some great looking cars. Too bad the beauty is only skin deep.