Delete more than 1 Track from Traktor DJ 2

Noby1968

Hallo can somebody help me. I have a database about 12.000 titles and lots of them can not be found when I want to play them. I have deleted the program and downloaded new but there were still the old tracks that can not be found. How can I delete more than 1 track? I can only highlight single tracks and not more to delete them. Is there a combination of keys or how can I reinstall the software pure without tracks? It is very urgent because I have dj gig next weekend and need this program to play.