Maybe, for your creativities sake, you should use a simpler program as a goto for your basic idea sketchpad. Then bring it into Cubase 7.5 for fine tuning.
But also think this. As this type of post appears only once every year or so (and may also attract the odd “+1 me too, I’ve had it since 1863 and so did grandpa.”) maybe the way your rig is set up might need a good looking at even if it is top notch and custom built. Even custom builds have had their problems (even some of mine). Solutions are surprisingly close sometimes. Infuriating too, though.
Have you ever posted anything in the Issues section of the forum?
Selling Cubase? Hm. 
See you next year. 
You mean, imposing your own absolute horribly devastating situation on another fellow human being?
A guys got to make a profit and cheer himself up somehow.