Nero vision

Have been using Nero 7 ultimate with no real problems for some time
Suddenly hitting a problem when using nero vision 4.
Hit the button to add video files to produce a dvd from hard-drive filesa and the browse folder doesn’t open !
Similar thing on nero express - can’t add files / folders
Any ideas how to rectify this please !
A new installation on another computer nero vision 4 works perfectly.
Thaanks !