Answer to "My screen goes blank when I open it pass 45 degrees"I have seen this problem many times and the cause is usually a bad connection between the screen, and the motherboard. If you pry the plastic band around the screen off carefully (I recommend starting from the bottom middle where you can see the SAMSUNG logo), you can see the connections on the bottom left hand side of the screen. You can inspect for any obvious problems. When you are done the plactic that goes around the screen will snap back into place when you apply pressure all around it.
Answer to "My laptop freezes when I open the lid"It sounds like it could be a hard drive problem. Many hard drives can/will fail eventually. The best thing to do would have it be replaced.
Answer to "How can I make computer faster?"Another thing that helps is to clean out the fan vents of your computer. It is important to keep a clean computer!