S-Layer (and Reaktor) (http://twistedtools.com/shop/reaktor/s-layer/)
Metaphysical Function, Skanner (also for Reaktor)
GRM Tools
SoundMagic Spectral
Metasynth
Camel Audio Alchemy ("the best sampler there is")
Perhaps even NI FM8 or Sytrus.
Too many ways to approach "computer sounds".