My Acer Aspire 7720G has a black screen when I start it up. The laptop seems to still boot up, can here the windows log on sound and also able to type my password in and for it to un lock (again I hear the login sounds that confirms this).
My 1 year old daughter (not under my supervision but my mum's) was hitting all the keys on the laptop.
I have tried the FN key with the brightness option in case it was this however no joy. I don't think it's a bios issue as I would not be able to log in. I tried to connect a DVI to HD connection to pull the display through my TV however it was not auto detecting and as I can't select duplicate screen from control panel, not sure what the issue is. I know if you press the window key and P it is a shortcut for projecting the screen, however unsure how many times I have to push it.
Same has just happened to me last night...I suspect the LCD display is at fault...will not display anything, even bios startup. Laptop does boot ok though and when connected to external monitor is still usable. I just viewed a guide on how to replace the screen... http://www.laptopinventory.com/LaptopInventory.php/Acer...
...cost of a replacement is about $300. If you are handy wih a screw driver you might like to to the remove and assembly as per the video to check the cable behind the screen is properly connected but it is likely the fault is permanent and you will need to replace it.
The laptop is still quite useable with a external monitor so you an still back it up. Mind you for $500-$1000 you can buy a new i5 laptop! I hope this helps...the video in the url above was very helpful.