Lately my MacBook has been running a little slower than usual and it would keep freezing while using firefox. Today it did the same thing so I held down the power button to shut it off and reboot it. Now when I reboot it takes forever and when I finally get past the login it stays at my desktop background and nothing else shows up. The dock never loads nor does the bar at the top. I don't know why it's doing this. Any ideas of what I can do? Thanks!