HD Filled up after aborted backup

[CarlF]

I suggested my daughter try Super Duper.
After she had started the backup I cautioned her that it would take a while.
She said she didn't have that much time right then, so she stopped it but couldn't quit.

She rebooted and said that she then got a warning that she had 0MB on her HD.
Can you tell me how to find and delete whatever is eating up her space?

Thanks,
Carl;