Frameratre madness: Anyone seen this before?

Hello you chapsAfter a pause of a week or two and a refit to my equipment, I started again on my scenery, and ran into a very strange problem.Normally, I was getting 25-30fps moving up close to objects in FS2002, despite lots of autogen and many objects (library). Now, however, if I add any new objects, these will only give me 5-10fps, even though in the same scenery, the ones I made beforehand work as they always did.It is the same 5-10fps even for objects which I previously used successfully.I doesn't matter if I use library calls with FSSC or Gmax ground polygons with Makemdl, the result is always the same. Even if I place the new objects using a new bgl, the result is the same. I've tried reinstalling all the programmes, even making the scenery on another computer, same result.I tried reducing the size of the original scenery, thinking there might some sort of upper limit to the numbers of objects but this didn't work either.The new objects only gave a reasonable frame rate if I removed the original scenery, but that doesn't really help me though, if I should have to make the whole thing all over again.Anyone any suggestions ?Jerry