Weird Laptop Problems

Hey guys, I just wanted help on some problems I have been having with my laptop.
-Sometimes when I close the lid, the laptop stays on, but the screen goes black. It should go to sleep when I shut it, but it occasionally does this instead. The only solution I have to this issue is restarting it manually.

-Another issue is the fact that if the laptop manages to go to sleep successfully, when I open it back up and press a key to wake it up, it hums really loudly and turns itself off.

None of these events are supposed to be done by the machine, because it tells me that the computer didn't shut down successfully when I turn it back on.

Here are my specs:
Acer Aspire 4920 Laptop
Windows Vista Home Premium 32 bit
2GB ram
Intel(R) Core(TM)2 Duo CPU T5250 @ 1.50GHz 1.50 GHz (That's copied from the system information menu)

Help please

 

Acer Aspires have a tendency to overheat. I used to have a big-ass Acer laptop which only ran for about 30min's before shutting down.

I used to have an Advent laptop that if you moved the screen suddenly the backlight turned off and it required you to turn it off manually and restart. Can you see the desktop on the screen very faintly? Or does the entire screen turn off.

 

Well, I can't see anything at all on it, from any angle. I'm not entirely sure if the screen completely turns off, because it still has this sort of bright, 'turned on' look to it. It just won't do anything once its reached that point. If it's left to its own devices when it's in that state it eventually just shuts down in the same way the laptop would if you held down the power button.

I'm using the laptop on a solid surface now, so the fans are more effective Before, I was running it inside its case, its just a little zip up sleeve that fits around the laptop, so when you are done you just close it and zip it up. I have noticed that both of these problems are less frequent now, but they still occur, and they are VERY annoying.

 

Windows has several different modes of shutting down. Aside from a full shutdown, there is Stand By, Sleep, and Hibernate. You may want to try a different mode of shutdown and see if the problem persists.