Do you often watch movies and videos online? Internet Options-General-(Browser History) Settings-Is the temporary Internet file large? If you have space to watch movies online, it's enough to adjust the island and 3G. Deleting temporary Internet files may have "accumulated" too much before.

In addition, QQ should not be installed on disk C, its volume will continue to expand. Don't stuff unnecessary things on the C drive.

It's too exaggerated to say 50G on C disk, as long as you like it.

There is not much in my document, because my document is on drive C.

In the case of hiding files and system files, there should be only these folders (documents and settings) (PROROM files) (Windows) on drive C, which are useless and can be deleted (Note! Is that system files and hidden files are not displayed! )