Don`t know how it happened but deleting them is easy enough. Go into Windows Explorer (Windows Key + E Key) In the left hand pane click on My Documents. In the right click on the column header "Type" and this will put all the zip files together. Now either click once on the first and holding the shift key click once on the last - this will select them all. Shift + Delete Key will delete them permanently. If you want to select the files individually hold the Ctrl key and click on the files to select specific one`s.