I think I have good news for you.
Canon issued an advisory on several cameras that has to do with a defective sensor. The A75 is one of them.
It uses a Sony sensor that had manufacturing defects.
Canon will fix the camera for free, even if it is out of warranty.
Here is a link that should get you started:
My camera's display (when I am in shooting mode) is all screwed up... i get funny cyan, magenta-ish color hues on the display, I can't see the subject and even on clicking i get the same image!! Camera works perfectly when I switch to preview mode and browse photographs.
Any ideas on what could be the issue here?