Thanks for your responses,

So I actually did try the two button reset last night, but I wasn't sure if it did reset any of the data since I didn't see any change on the display. After half an hour of fiddling and trying to fix the auto focus, I turned the camera off. Now, when I turn it back on without changing or pressing any button except the "on" button, it started working all of a sudden!

I don't know if this is the problem, but yesterday night I was testing out the camera in the dark...with not much light. However, the lens motor didn't even run on all three of the lens I tested out last night. Just right now, I'm in a well light room, so would this be the problem?

As for cleaning the mirror and the insides, would I need to do anything prior to using a brush? I saw a video where in the dslr you have to have to push some button to drop down some part to clean.