Where did my systems preferences go?

I have a 15" MacBook Pro, Version 10.6.8. I've had it since 2009 (old, I know). It's been great so far, but today I went to go to my Systems Preferences and it's not there. I clicked on the Apple Icon in the top left: nothing. I did a spotlight search: same result. I went to my applications folder: same thing. I can't open any of my preferences from any other source (i.e., if I want to look at my network preferences, I normally click on my WiFi symbol and click "Open Network Preferences" on the top toolbar. Nothing happens when I do this.). It's not really impeding any of my computer's normal functions; I would just like to know where it is. I currently have Snow Leopard as my operating system. Would it help if I installed Mountain Lion OS? Some friends say that that would help, and I'm not averse to paying the money for it. I just want to know if there's another solution before I do that.