Screen won't turn on

Hi
Apologies if this has already been posted as I'm new to this site. I'm having trouble as my laptop screen has gone completely blank.
Its an Acer Aspire 5520 running Vista, it was working perfectly and then once i restarted it and the screen never came on since. First time i restarted it though and the screen didn't come on I did hear the vista sound start up, although now it doesn't (could be as I turned it off without shutting down an as a result is going to the repair boot up part).
I've checked very closely at the screen in case its just the backlight turned off but I still see nothing. The only problem I used to get is that the screen used to go all weird an blurry an pictures was placed randomly (kinda hard to describe).
Also I tried connecting it to an external monitor an nothing was displayed (monitor couldn't find a connection an went to sleep) although that could just be as its not configured to use an external monitor.
Any help would be great thanks

1.  Video Subsystem.  My best guess is you've lost your integrated video (as in broken/dead).  Someone more familiar with laptops would need to opine as to your options (whether it can be fixed or video subsystem replaced).

From Acer Aspire 5520 Specification(s):

Video Subsystem    ATI Radeon X1250 integrated 3D graphics with up to 896 MB of HyperMemory (256 MB of dedicated system memory, up to 640 MB of shared system memory), supporting Microsoft DirectX 9, PCI Express

2.  Troubleshooting.  I'd hook the external display up again and continue troubleshooting.  Using the <F2> key at system startup should take you into CMOS setup to permit you to modify BIOS parameters.  If power is good, and you can't get anything to display anywhere at any time; then I'd say your video subsystem is dead.

On general principle, I'd troubleshoot with the battery out and AC power adaptor connected (to eliminate the battery as the source of any potential problems); but I don't think it will make a difference here.

From your user's guide:

Page 31.  Hotkeys.  The computer employs hotkeys or key combinations to access most of the computer's controls like screen brightness, volume output and the BIOS utility.  To activate hotkeys, press and hold the <Fn> key before pressing the other key in the hotkey combination.

<Fn> + <F4>.  Sleep.  Puts the computer in Sleep mode.

<Fn> + <F5>.  Display toggle.  Switches display output between the display screen, external monitor (if connected) and both.

<Fn> + <F6>.  Screen blank.  Turns the display screen backlight off to save power.  Press any key to return.

<Fn> + <right-arrow>.  Brightness up.  Increases the screen brightness.

Page 40.  Nothing appears on the screen.

The computer's power management system automatically blanks the screen to save power.  Press any key to turn the display back on.

If pressing a key does not turn the display back on, three things might be the cause:
     o  The brightness level might be too low.  Press <Fn> + <right-arrow key> (increase) to adjust the brightness level.
     o  The display device might be set to an external monitor.  Press the display toggle hotkey <Fn> + <F5> to toggle the display back to the computer.
     o  If the Sleep indicator is lit, the computer is in Sleep mode.  Press and release the power button to resume.

3.  Reference(s):
     Acer Support - Aspire 5520

Hi
Thanks you found a lot more information then I could. I wanted to try pressing F2 at the start but I'm not sure when as I cant see anything on both monitors?
I tried with battery in and battery out  and with the AC cord and without but still the same. Also tried changing the brightness to no avail. I think I might give the external screen one more go then go with thinking the video subsystem needing to be replaced?