not all temporary internet files are cookies, they are two different things. Cookies are placed on your computer by web pages you have visited and are there so they can tell if you have visited before, the temp internet file cache it just to help your Page reload faster if you want to open it up again. I delete all temp files as I close my browser & I delete all cookies except the ones I want to keep such as my bank. No harm will come if you delete everything. Go to Control Panel/ internet Options/under the General Tab click Delete Files & if you wish click Delete Cookies. You are right too many Temp files can slow your computer down.