Could be low on resourses. hit Ctrl/alt/del together and see what is running in the background. End Task on all you do not need. also try disableing any anti-virus software running.
Could also try and create a multi session disk and dump backups in bits.
The symptoms described could be related to low memory.
Also Try drag and drop to the CD drive and use xp's built in feature. If this works then you know that its Nero using too much memory