Nero back it up

Can anyone help me with Nero Back it Up 7. I copied the program (I thought) onto a disk, then used the downloaded program to back up my files. Later my computer crashed and I am trying to restore. But when I put the disk on which I had saved the program into the computer, I couldn’t run it to restore my files. I can see my backed-up files on my external drive but they have an explorer icons next to them–not the nero icon. What to do? Can I ask to have the program downloaded again if I have the serial number? Anyone know where I can go for help with this?