You can make ONE single backup of YOUR OWN disks for your personal use, assuming the software is not copy-protected.
If the disks are software protected then you may not make any copies at all, since breaking the protection for the purpose of making a copy would be a breach of the Digital Millennium Copyright Act and possibly lead to jail time.
You cannot download adf's, and you cannot obtain backups from another source, even if you own the original. The 'copy' you use must be the one you made yourself. This is very made clear in copyright law.
If your Workbench disks are corrupted and you don't have backups then tough luck you need to find some replacement originals.
