Don't copy the whole disk at once but drag and drop the invividual files from your CD drive to a new folder on your C drive. When you have done this copy the contents of the folder back to a CD (You will not be able to drag and drop any corrupt files however).
If there are errors on your CD then Nero will tend to "hang" at the corrupt file and not go any further.
If you have important date dont rely on CDRW's alone as these are prone to unrecoverable errors. Backup your files to a CDR.