I dont know why this happen, but if im not typing and i just watching a movie on the computer it turn off by itself.If you know why this happen tell me please. Thank you.
Its because it is set to turn off at a certain time by default.
If your using a windows 7 computer this is how to fix it:
1. Go to start menu(bottom left corner).
2. Press Control Panel(on the right side of the start menu).
3. Search "Choose when to turn off display" (top right corner)
4. Click the only option left.
5. Go down to "Put the computer to sleep".
6. Press "never"
Another way to fix it if your using windows 7:
1. Click the battery on the bottom right of your screen
2. Click "More power options".
3. Click "Choose when to turn off the display" or "Put the computer to sleep".
If your using a mac you'll have to get an answer from someone else because I don't know enough about it.
check the sittings