Mystery of the missing planes

I have the Wilco PIC B767 installed in FS2000. Yesterday, I tried to select a PIC B767 in the aircraft section of FS2000, but there were no planes in that category. I also tried in the saved flights page, where I had stored some PIC flights, but I got an error message about initialization of aircraft not possible.I closed FS, and looked in the FS directory, in the aircraft library,. Sure enough, the PIC files were there, all five planes that I had originally installed, ( patch also).I do remember that prior to this disappearance, I downloaded some big SID, STAR, and Approach files into the FMC folder, (the FMCWP folder).Could this have caused the planes not to show up in FS. I doubt it. So what's the problem? Why aren't the PIC planes not showing up in the aircraft page?Totally dumbfounded.Eytan OrnsteinTJSJ