When you say. "Disk clean up", what exactly do you mean?
Do you mean wiping and reformatting or just emptying temp files?
Emptying temp files should not have impacted the operation of IE or changed what you had stored in your favorites.
You can repair Internet Explorer, but unless you had your "favorites" backed up, if he deleted them they are gone.
Click to Control Panel, then to Add/Remove Programs, and then to "Microsoft Internet Explorer 5.x." (Your copy may call itself Microsoft Internet Explorer 5.x (or 6) and Internet Tools," or something similar, but your get the idea.)
The next step is not at all intuitive, but click the "Add/Remove…" button, and instead of triggering an uninstall, you'll find the repair tool.
The tool gives you the option of repairing your current installation (this is usually the correct choice), or reverting to your previous installation, if you elected to make a backup of that installation when you first installed IE 5+.
Edited by Enthusiast, 10 March 2006 - 11:41 AM.