thx, already did so as i am impatient
btw having a lot of experience with Windows i keep several copies of my precious files (at home and online backup with my provider) - one never knows ...
meanwhile ..... after i rebuild my library and everything was okay again i still get duplicate files for example one i do the following:
1) download a zip from internet to d:\temp
2) next unzip directly to my d:\music folder
3) a voila again duplicate files eventhough there is only one file present physically
when i unzip to temp and next copy paste to music folder all is fine