Downloaded and Installed on USB but it won't install. It has errors, but I can't remember what it said. Can I download a fresh copy again?
Yes, you certainly can download a new ISO. You can verify the download using the hash listed here: https://elementary.io/en/docs/installation#creating-an-installation-medium The hash is listed under the section "Creating an Install Drive"
What software did you use to make the USB? I recently created a successful USB drive using Etcher. I've tried Rufus before and it also worked.