When I open the lid of my laptop fully, the screen goes black.

what configuration of the power manager do you use? laptop goes to hibernation mode automatically or by pressing the power button or by closing the lid?

There is a loosing in circuit board, you might not be able to fix this problem by your self it needs technical proficiency

It should be a Problem of a loose conection.
if you feel you are good to take it apart there are a lot of tutorials on the web in how to take it apart and reattach the flex cable. (maybe even change it)
otherwise take it to a laptop specialist

REplace the flexible cable that feeds the screen from the motherboard if it is damaged or just plug the cable in as it may not be connecting properly.

Look closely at the area where the computer "folds";
there's a small sensor that should trigger when you *CLOSE* the lid -- perhaps, something is triggering that sensor (a small pin) when you're exceeding 90 degrees, putting the computer to "sleep".

There is a thin ribbon cable that runs between your screen and the rest of the laptop. every time you open/close the lid it flexes that cable.
Something in your cable is coming loose, it could be that a wire in the cable is broken and connects only at certain screen angles or perhaps one end of the cable is loose.
You need to take the bezel off to get to the cable, verify that the cable is plugged in, if the problem still occurs then replace the cable.
You should find the cable fairly cheaply on ebay, search for acer "model" lcd ribbon cable.

Let me know if this helps.

There are a few things that could have happened, the most likely that one of you cable clips is loose, and when you open it fully, it pulls it out just enough so that the connection is lost.

Your going to need to open your DS, (the forms at www.powergamingparts.com are the best forms to find these instructions) then just disable your clip, and reinsert it, and then close the clip, and put you DS back together. Just ask if you need any additional help.

You just need to diable presentation mode.It's not the switch.

Hi, This is definitely a loose connection problem.
Does the screen go completely black or just a part ?
If its just a part, LCD is defective. You may have to change the whole LCD screen. You can get one for ~180$ from ebay
If the whole is turning off, I guess the power cable might be little loose.
You can open the LCD panel and check if you know what you are doing.
Else take it to a normal technician and ask him to open the LCD panel and see it.
:)