So your hard drive is still overloaded and you even afraid to install small programs of 5mb? Duplicate Files Deleter can help you here. It is small and is easy to use. You can find it on official site.
Before starting actual scanning you can set different settings. For instance, you can set to ignore file content or visa verse. You can scan hard drives only for big files > 50mb which use most of your space. You can also filter file extensions. If you want to find only duplicate songs, you can use file masks like: “*.mp3, *.3ga, *.flac, *.arf”. If you want to find only duplicate videos, you can use file masks like: “*.mkv *.flv, *.avi, *.wmv”.
More details you can find on DuplicateFilesDeleter.com