I'm from malaysia..i think i didn't run any 3rd program programs that will breaking the os..Before that i got format it one time than i change to chinese just want have a try but after i using chinese,the problem appearl when i want to format it and change back to english..when my macbook black runing in the format mode..it oso will freeze..after few times i try..it just can sucessfully format and go into the OS..But,in the OS also keeping on freeze and the system ask me to restart by press n hold the on off button..i'm very headache when see this problem..