I need more room on my C Drive in order for Live Update to run

I keep getting a "Critically low disk space on C drive" message as I do my daily grind.  Every week or so I get the warning about Live Update not being run.

 

Try as I may, I can't seem to make more room on my C drive - I am too inexperienced to know what is vital and what I can delete.

 

Does anyone have any suggestions of what I can do to alleviate this problem or perhaps there is a resource or document available that lists non-essential files, folders etc?