Unable to change TEMP folder locations

Hey all, I have an issue.
My C drive is a 64gb SSD. It has windows and basic documents and files. It has 1.5gb free. Ive looked thru everything and theres nothing i am willing to delete. And nothing of a size to bother moving.

My issue is. I have changed all the temp folders to my 2TB drive Q:
In both system variables and user variables both temps are set to Q.

However when running installers it still temp installs to C. Regardless of the fact its told to temp everything into Q:/temp

I have 3 programs i desperately need to install. first Visual Studio 2013. Ive set its install folder to Q.
But still it says it requires 6gb on C and 3Gb on Q

How can i stop it from writing to C completely... I have had this issue with any installer to be honest.

I could put my temp file locations anywhere any drive bar C and still itll write Temp to C.. This is something thats given me great frustration in the past and because of this - many many programs ive had to just get over and not bother installing due to this silly problem...

Its beyond me if all temp directories [system and user variables] have been set elsewhere and yet it still writes to C?

*facepalm

any help is greatly appreciated!