Why does my computer randomly crash to a Black Screen?

When I leave my computer for a couple of hours on screen saver, it tends to crash or go really slow, why? ?

• Or it lags badly and does weird things! Is it bad for a computer to sit around on screen saver? By the way, I am talking about a laptop! Thanks...

• Answer:

  Hardware heats up and doesn't run as well when it's burning hot - like a computer that has been on for days or weeks at a time. Sometimes even being on for 6-8 hours can make equipment sluggish. Turn off your computer when you aren't using it. It saves power, it saves your monitor (which is like a lightbulb - it only runs for so many thousands of hours and then you have to buy a new one...why use it up uselessly like that?), it saves your hard drive from heat damage, as well as your motherboard. It saves your fan bearings because the fans aren't turning 24/7 and therefore don't wear out as quickly. It's controversial. Some people will say leave it on, others will say turn it off. Do you stay awake 24/7? While it is a machine...it needs a 'rest' to cool down and dissipate heat. That's why it works 'better' when it's not hot and when you've first turned it on. The 'don't turn your computer off and on' thing used to be a big issue back in the 80's and possibly early 90's. Basically, the soldering on some components could come loose if you turned your computer off and on a lot - so people left them on. We don't have that problem with computers now, and that problem was solved quite rapidly. If you did it 20 or 30 times a day, you could wear out your power button after maybe a year. Also, a hard drive only has so many times that it's rated to "start and stop." Usually it's something like 20,000 times, though. People will say leave it on because "it's convenient" and "it keeps dust from getting it." But if your motherboard burns out due to heat damage, what's the point? Wear and tear is worse than dust, which can be sprayed out with airduster in just a few seconds. Laptops have a tendency to overheat in themselves, because they don't have a lot of room for cooling and they have a very small cool and heatsink. Imagine a heater in a small room where the door is never opened and there is only a small window to let the heat out. That room is your computer, and that window is your heatsink and fan. Also, the very reason for a "screensaver" was originally to keep the screen from having an imaging 'burned' into it due to the monitor displaying the same picture over and over for many hours. Many monitor manufacturers have fixed that problem, but it can still happen with some. Laptops are expensive, so don't destroy yours with heat damage by leaving it on all of the time. Forget the people who say to leave it on all of the time. Doing that will probably allow you to get a year or less of use before it burns out on you.