How do I wipe my hard drive clean?

Every time I go to DBAN, they won't let me download anything free. I can't get either of my disk drives to work because I have a trojan on my computer. I have to wipe my hard drive clean before I reformat my windows. I tried sending in ground troops and a brigade to fight the enemy. Now, I'm stuck with Plan B which is to send in an air strike. I already have everything I want saved on hard drive. Does anyone know of a website that has a list of instructions how to use DBAN?