How can I have more disk space on my computer ? How do I clean it up ?

The disk space on my computer for (C:), has only 1.89GB of 137GB free…. So I barely have any space left.

How can I clear this up ?

Will Disk Deframenter create more space ?

Does anyone know how to deleted users from the computer also ? I created different user accounts, and I think some might still have files on them. I’m not sure where all my space went.

Thanks