Have an Acer 7520 with black screen on startup. What can I do?

Aspire7520

Hi. I have an Acer Aspire 7520 which is giving me black screens at each start up. This happened after I had unscrewed the backside to remove the dust from the fan with a vacuum cleaner. I have checked the HD on another laptop and it was ok. I already tried to log on a external screen, but that did not give any result. The leds of the electrical power and (if it's installed) the battery are working. And also the led of the HD flashes temporarely but it doesn't give the sound of a 'full action' HD. On startup the DVD drive also seems to activate, but trying to startup on a recovery disc doesn't work. Pressing F2/F8 or ESC+Fn doesn't help either. What else can I try or does somebody know what could be the problem?

Blayn-Acer

You can try making sure the backlight is enabled by pressing FN + F6, or making sure it is not set to display to an external video source by pressing FN + F5. If that does not resolve your issue, you can try a power reset using the instructions at http://acer.custhelp.com/app/answers/detail/a_id/13677. If that does not resolve your issue, you may try contacting Acer Technical support in your region.