STORAGE RECOVERY FROM INSTALLING DEMO'S

Good day, 
Can anyone tell where to look to recover significant C drive storage taken up in loading and using demo software. 
I download to secondary drives, but install to C:, Ive uninstalled all demo's and related programs I could see through Control panel, but dont seem to recover much space, and Im talking like in the order of ~ 50G of space? 
I also notice some small glitches in Sonar processing I didn't have before doing all this demo-ing  like when bouncing clips and exporting mixes, I see little windows popping up quickly that seem to relate to AI (RME-UFX) channels, they flash pretty quickly so hard to see exactly what they are, albeit all seems to work OK, its just unfamiliar.
 
Any guidance would be appreciated.
 
Cheers  

K, seems I recovered a lot if anyone else has this issue under
 
C:\Users\John\Downloads\Steinberg\WIN64  = ~ 40 gig in space
 
Although I downloaded all Cubase stuff to my E drive, it seems to all also show up here also, both zip and unzipped files.
 
Cheers