Low Disc Space

Just the last couple of days, I have been getting a low disc space warning. It is for Drive C. I have removed as much as I think I safely can, but now the virus scan can't run because of the low disc space.

Does anybody know of anything else I can safely do to free up anymore space?

I think some things got duplicated, as I am seeing in my documents folder, on Word, all kinds of ext files, which have never been there. If I knew how to do a screen shot, I could post the index of that, and maybe somebody can tell me where these things actually go, and I could check to see if they have been duplicated.

I would appreciate any help anybody can give. I am thinking about a new computer, but hadn't anticipated doing it right now.