Green algae - HELP please!!!

[mexxedm]

Hello,
My tank had bad green algae. All the stuffs died. I start from fresh but still use the existing rock and sand bed. Now algae starts growing back again. I don't know what to do. Is there any medication that helps killing algae? I lost huge amount of money that I invested because of that stupid green algae. I don't want to be a loser the second time. I am desperate needing help.
Thank you very much in advance.