Flaking on the inside of the LCD screen.

sounds like its over heating,clean the fan out

If you show a Blue Screen, you have more problems then it not being able to turn off/shut down?? I would back out the battery so as to stop power from getting to it, AFTER you have it unplugged..then push battery back into to engage, plug the AC cord back into the PC. turn it back on and IF you still show a BLUE screen, you will need a tech to check it further...GOOD LUCK...

check the ram chips havent come loose, i had this problem with an acer aspire 5315 (fixed myself). if that doesn't work, check the lcd cable

It might be going into sleep mode or hibernate mode.

Try removeing the battery, memory and Hard drive. Press and hold the power button for 30 seconds.
Re-install and reseat memory Harddrive and battery.
Try powering up the unit without the battery and any external devices.

The power button may not work, that is most common in laptops, or you have a short.

Remove power cord, remove barttery. Reinsert battery. Plug in power cord. Turn on.

There might be problem with signal cable of the LCD,Had you tried with external display .If same problem with external disaply then might your graphics card problem ,if not then certain problem in signal cable or the screen itself

I have had the same problem,
I found it was my power supply transformer (part of power lead).
Some transformers may be faulty, or replacement transformer may not provide a voltage stable enough for the LCD.
Also check the wiring in your plug.
Safest option is, buy a genuine Acer supply transformer with plug lead from Acer.

Hope this helps (please rate my advice)

try pressing on fn+f5 or fn+f6 a couple of times each. Maybe the screen got switched to projector status by mistake.