Files being downloaded from the Internet or attachments to emails get stored in the Downloads folder located in your U: drive. If you want to save that file, you should save it to an appropriate folder in your U: drive. Very often that results in duplicate versions of the same file – the one in your Downloads folder and another one in your U:\ drive. For this reason, it is recommended that you periodically empty the Downloads folder.
Open My Computer and navigate to your U: drive
Double click on Downloads
Make sure that you are in the Downloads Folder. Select all files by holding down Ctrl + A
Hit the Delete key on your keyboard.
This will move all of the files to your recycle bin. To reclaim the space:
Right click on the Recycle Bin on your desktop and choose Empty Recycle Bin