How to Clean an External Hard Driveby Andrew Todd
Windows Vista and Windows 7 both include a utility called Disk Cleanup, which can be used on both internal and external drives to remove unnecessary and temporary files. Once these files are removed, the space available on the volume will be increased and your system may operate faster. It is good practice to periodically cleanup all of your hard disks, because temporary and unneeded files are constantly being saved to your hard drives as a result of Web browsing and the installation of programs and updates.
Open the Start Menu and type "Disk Cleanup" into the search box.
Select the Disk Cleanup program when it appears in the search results on the Start menu.
Select the external hard drive that you would like to clean up from the drop-down menu and click "OK." The system will now scan the drive to detect any unnecessary files contained on the drive.
Place a check mark beside each item category that you would like to delete. Click "OK" and then confirm that you would like to delete the files to complete the disk cleanup process.