Hi, I am pretty new to macs. I have my first one right now and i keep running into a problem. I was trying to change my desktop theme, and every-time i got to that window, the system preferences program keeps closing and saying there is an error. Im not sure why this all of a sudden occurred. But it won't let me do anything before closing and Im beginning to get really frustrated. So i was wondering if i could do some kind of system restore, like on a p.c., to put it back to yesterdays settings, so that maybe i wouldn't have this problem anymore. or if there is something else i can do. i need help!!!!!!!!!!!!!