How To Use Disk Cleanup

1. Click Start, point to All Programs, point to Accessories, point to System Tools,
and then click Disk Cleanup. If several drives are available, you might be
prompted to specify which drive you want to clean.

Disk Cleanup calculates the amount of space you will be able to free.

2. In the Disk Cleanup for dialog box, scroll through the content of the Files to
delete list.

Choose the files that you want to delete.

3. Clear the check boxes for files that you don't want to delete, and then click OK.

4. When prompted to confirm that you want to delete the specified files, click Yes.

After a few minutes, the process completes and the Disk Cleanup dialog box closes, leaving your computer cleaner and performing better.

Source : Microsoft