I tried to upgrade from 7 to 9. Install unsuccessful. But I'm short the amount of disc space of the downloaded update. It seems it didn't give the space back to me. That's about 30-50 MB. I can't find where that download might be stored in the system.
After about 3 days and some reboots my space seems to be where I thot it should be. Strange things can happen with programs using and releasing space. It seems like it was Adobe. It should have been released after one reboot, not to mention before any reboot.