Display going Blank/Black on Starting the Laptop

My Acer Aspire 5742 Z went Blank/Black when I logged off after using it the whole day from morning for downloading. It also makes "Long Discontinuous Beep-Beep Sound" on starting it every time after shuting it down. I read the Nanor and Baldi68's Solution but havent yet done it because mine is Acer Aspire and their solution is for HP Laptops. So will it create a problem if I do it on Acer Aspire Laptop?? I'm Clueless as I done have much knowledge about Laptops/Computers. Also my battery gets used up very fast. It lasts for 30/45 minutes after charging fully to 100%. So can battery or any Hardware problem be responsible for Display going Blank/Black? Also Lookinf for some solution for "Long Discontinuous Beep Sound" It started all of sudden. Absolutely have no idea why it started. Suggestions will be very helpful to me. Please.