If the problem persists, you might try using DVD burning software instead of drag/drop to create your disks. There are a number of free apps available.
Some antiviral software (eg, Avast) has been known to cause drag/drop freezes with Vista, so you also might try disabling your antiviral/antimalware suite and then try to create a disk. If that helps, you may need to reinstall the antiviral/antimalware suite or try a different one. There are lots of free ones, eg Microsoft Security Essentials etc. But be sure to reenable it before you forget and go on line. 