Got a laptop Aspire 7520, laptop loads starts up fine but the screen has gone black, can hardly see the desktop display. have tried adjusting the brightness of the laptop but still desktop display can not be seen.

To fix this problem it will require you to physically open up your laptop , which will probably void you warranty , so please get this replaced under warranty if possible , if your not worried do the following.

Remove all the screws holding the laptop's shell together and open up behind the laptops screen , there are two connectors here which you will require to check , the power connector which is a small black connector and the more prominent video ribbon connector make sure these two cables are connected properly,

You may discover that you have a faulty LCD screen either get it replaced by a trained technician or do it your self (your halfway there anyway)

You may also find that the cables became dislodged and this fixed your problem.

Though it could also be a software issue probably within the graphics cards application , i see you have checked brightness but have you checked all options to change it ?

This is a hard one

Goodluck