nuendo 5 initial vst plugin scan problem

somehow i added c:/program files/ to my plugin paths and now hwnever i try to run nuendo it scans perpetually (because program files is full of *.dll files) and it eventually crashes after some time.
I tried searching registry for that plugin path entry but couldnt find anything.
Of course, i reinstalled nuendo5 but it didnt help… information about plugin paths is obviously stored somewhere in windows and now nuendo is useless.
Any info on how to solve this problem?