How come I am having problems installing Internet Explorer?

Q: Tried to download IE6. Computer said I had a newer version. When I do a CCleaner, all the files are listed as IE5. Had IE7 SP2 until I did a reload of XP and everything went south after that. Had Mozilla Firefox, deleted that and put in Google Chrome, then deleted that and reinstalled Firefox. I am a “sub” “Computers for Dummies and know I have messed up completely. How do I delete whatever IE’s I have and download straight to IE 7 SP 2 ? Thanks OneMonday