A couple of weeks ago my Macbook pro started crashing, and I can't use it without it freezing every fifteen minutes. Any suggestions before I go to the Apple Store? It's running Snow Leopard, 13" and I bought it in August 2010. It crashed a couple of times at first, then it wouldn't boot at all (it froze usually at the gray screen as the wheel spun), so I brought to the Apple Store only for it to mysteriously start working again when I got there. It worked for a couple of days only to start freezing again. Now I can't use it for more than fifteen minutes or so at a time. Usually its fans start to act up, it slows down then stops with the screen frozen and fans whizzing. The last time I tried using it it said it didn't recognize the airport card and couldn't connect online, but I haven't used it since then so I don't know if it still says that.

So my question is: is there anything I can do, anything I might be overlooking? I tried updating its software but that didn't fix anything. Or is there anything I should do before I go to the Apple Store? Thanks.