1. Click "Show all files and folders" in Folder Options (as shown in the following figure).

If there is a dollar sign in the windows folder, all the files are junk files left after the operating system updates the patch and can be deleted manually. As shown in the figure below, the file is circled in red.

2. Use third-party software to slim down the operating system, such as XP slimming tool and Win7 slimming tool. The following are XP system weight loss tools. Users can download and use this tool to lose weight in the operating system, and delete other "unnecessary" files such as input methods, languages and help files that are not needed in the system.

3. Use "Data Transfer Tool" to transfer all kinds of temporary folders on drive C, just refer to the following steps marked 1, 2 and 3.

4. Use various "garbage cleaning" tools to delete the garbage in the operating system, such as the garbage cleaning tool in Security Guard 360.

After the above steps, the space in the operating system can be completely released. If the computer uses a mechanical hard disk, it can also defragment all its partitions to further improve the operating efficiency.