BB Bold :: Why Does It Turned Off By Itself

ok so i downloaded a video yesterday to my phone cause in order to watch it, i need to save it and so i did. it wasn't the first time i did it, i i did quite a lot and so i tried to go the videos and open it, instead my bb turned of by itself and the screen turned white and blurry whenever i opened the video from my phone. i thought that the memory card itself was broken but it wasn't, i can still see the pictures and my musics. i tried to connect my phone to the computer with the cable used to sync musics, pictures, etc to my phone and when i checked the videos, there wasn't any video in it in the file itself. i was confused and for some reason it also turned off even though i didn't press anything and it rebooted itself and i guess it happened like this when i downloaded that video. is there any chance of repairing it? my brother said that he himself had gone through the same problem as me and he said to me to take the battery out and leave it for a day and it'll turn back to normal but i don't know if it's going to be ok though so is there any other easy solution?