Finder isn't working? Plus seversl other issues

I have a MacBook Pro, and this afternoon the Internet stopped working. It's stormy out, so I figured that was the issue, and I left for a few hours. I came back and tried to connect to the Internet, but it still wasn't working. I opened system preferences without an issue, but it froze as soon as I clicked on network. I tried to open a finder window, but finder wouldn't respond, even after I relaunched it. I restarted my computer, and everything on my desktop, including Macintosh HD, had disappeared, as well as the tool bar at the to of the screen that shows the application, time, wifi none cation, etc. Finder still wouldn't respond when I tried to open a window. Like before, I could open system preferences without an issue, but it froze as soon as I clicked network. Stupidly, I tried to restart again, and now it's stuck on a white screen. The apple logo isn't there, but I can see and move the little arrow.

I'm not sure which OS I have, but I'm pretty sure it's a version of lion. I would check, but I'm frozen somewhere in the restart process. Also, for the record, I'm on my iPad right now and it connects to the Internet without a problem.